diff --git a/Makefile b/Makefile
index a1044d3..5f30bb4 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,18 @@ CFLAGS += $(LIBRESSL_PREFIX:%=-I%/include)
 LDFLAGS += $(LIBRESSL_PREFIX:%=-L%/lib)
 LDLIBS = -lcursesw -ltls
 
-OBJS = chat.o edit.o handle.o input.o irc.o pls.o tab.o tag.o term.o ui.o url.o
+OBJS += chat.o
+OBJS += edit.o
+OBJS += handle.o
+OBJS += input.o
+OBJS += irc.o
+OBJS += log.o
+OBJS += pls.o
+OBJS += tab.o
+OBJS += tag.o
+OBJS += term.o
+OBJS += ui.o
+OBJS += url.o
 
 all: tags chat
 
diff --git a/chat.c b/chat.c
index 9d5a323..050a4f0 100644
--- a/chat.c
+++ b/chat.c
@@ -161,11 +161,12 @@ int main(int argc, char *argv[]) {
 	const char *webirc = NULL;
 
 	int opt;
-	while (0 < (opt = getopt(argc, argv, "W:h:j:n:p:u:vw:"))) {
+	while (0 < (opt = getopt(argc, argv, "W:h:j:l:n:p:u:vw:"))) {
 		switch (opt) {
 			break; case 'W': webirc = optarg;
 			break; case 'h': host = strdup(optarg);
 			break; case 'j': selfJoin(optarg);
+			break; case 'l': logOpen(optarg);
 			break; case 'n': selfNick(optarg);
 			break; case 'p': port = optarg;
 			break; case 'u': selfUser(optarg);
diff --git a/chat.h b/chat.h
index c66683b..51494de 100644
--- a/chat.h
+++ b/chat.h
@@ -154,6 +154,11 @@ void urlScan(struct Tag tag, const char *str);
 void urlList(struct Tag tag);
 void urlOpen(struct Tag tag, size_t at, size_t to);
 
+void logOpen(const char *path);
+void logFmt(
+	struct Tag tag, const time_t *ts, const char *format, ...
+) __attribute__((format(printf, 3, 4)));
+
 void spawn(char *const argv[]);
 
 wchar_t *ambstowcs(const char *src);
diff --git a/handle.c b/handle.c
index 71fab12..89d101a 100644
--- a/handle.c
+++ b/handle.c
@@ -166,6 +166,7 @@ static void handleJoin(char *prefix, char *params) {
 		"\3%d%s\3 arrives in \3%d%s\3",
 		color(user), nick, color(chan), chan
 	);
+	logFmt(tag, NULL, "%s arrives in %s", nick, chan);
 }
 
 static void handlePart(char *prefix, char *params) {
@@ -184,14 +185,16 @@ static void handlePart(char *prefix, char *params) {
 		uiFmt(
 			tag, UI_COLD,
 			"\3%d%s\3 leaves \3%d%s\3, \"%s\"",
-			color(user), nick, color(chan), chan, mesg
+			color(user), nick, color(chan), chan, dequote(mesg)
 		);
+		logFmt(tag, NULL, "%s leaves %s, \"%s\"", nick, chan, dequote(mesg));
 	} else {
 		uiFmt(
 			tag, UI_COLD,
 			"\3%d%s\3 leaves \3%d%s\3",
 			color(user), nick, color(chan), chan
 		);
+		logFmt(tag, NULL, "%s leaves %s", nick, chan);
 	}
 }
 
@@ -215,12 +218,17 @@ static void handleKick(char *prefix, char *params) {
 			color(user), nick, color(kick), kick, color(chan), chan,
 			dequote(mesg)
 		);
+		logFmt(
+			tag, NULL,
+			"%s kicks %s out of %s, \"%s\"", nick, kick, chan, dequote(mesg)
+		);
 	} else {
 		uiFmt(
 			tag, (kicked ? UI_HOT : UI_COLD),
 			"\3%d%s\3 kicks \3%d%s\3 out of \3%d%s\3",
 			color(user), nick, color(kick), kick, color(chan), chan
 		);
+		logFmt(tag, NULL, "%s kicks %s out of %s", nick, kick, chan);
 	}
 }
 
@@ -239,8 +247,10 @@ static void handleQuit(char *prefix, char *params) {
 				"\3%d%s\3 leaves, \"%s\"",
 				color(user), nick, dequote(mesg)
 			);
+			logFmt(tag, NULL, "%s leaves, \"%s\"", nick, dequote(mesg));
 		} else {
 			uiFmt(tag, UI_COLD, "\3%d%s\3 leaves", color(user), nick);
+			logFmt(tag, NULL, "%s leaves", nick);
 		}
 	}
 }
@@ -257,6 +267,7 @@ static void handleReplyTopic(char *prefix, char *params) {
 		"The sign in \3%d%s\3 reads, \"%s\"",
 		color(chan), chan, topic
 	);
+	logFmt(tag, NULL, "The sign in %s reads, \"%s\"", chan, topic);
 }
 
 static void handleTopic(char *prefix, char *params) {
@@ -273,6 +284,7 @@ static void handleTopic(char *prefix, char *params) {
 		"\3%d%s\3 places a new sign in \3%d%s\3, \"%s\"",
 		color(user), nick, color(chan), chan, topic
 	);
+	logFmt(tag, NULL, "%s places a new sign in %s, \"%s\"", nick, chan, topic);
 }
 
 static void handleReplyEndOfNames(char *prefix, char *params) {
@@ -335,6 +347,7 @@ static void handleNick(char *prefix, char *params) {
 			"\3%d%s\3 is now known as \3%d%s\3",
 			color(user), prev, color(user), next
 		);
+		logFmt(tag, NULL, "%s is now known as %s", prev, next);
 	}
 }
 
@@ -354,6 +367,7 @@ static void handleCTCP(struct Tag tag, char *nick, char *user, char *mesg) {
 		"%c\3%d* %s\17 %s",
 		ping["\17\26"], color(user), nick, params
 	);
+	logFmt(tag, NULL, "* %s %s", nick, params);
 }
 
 static void handlePrivmsg(char *prefix, char *params) {
@@ -375,6 +389,7 @@ static void handlePrivmsg(char *prefix, char *params) {
 		"%c\3%d%c%s%c\17 %s",
 		ping["\17\26"], color(user), self["<("], nick, self[">)"], mesg
 	);
+	logFmt(tag, NULL, "<%s> %s", nick, mesg);
 }
 
 static void handleNotice(char *prefix, char *params) {
@@ -393,6 +408,7 @@ static void handleNotice(char *prefix, char *params) {
 		"%c\3%d-%s-\17 %s",
 		ping["\17\26"], color(user), nick, mesg
 	);
+	logFmt(tag, NULL, "-%s- %s", nick, mesg);
 }
 
 static const struct {
diff --git a/log.c b/log.c
new file mode 100644
index 0000000..2a47806
--- /dev/null
+++ b/log.c
@@ -0,0 +1,121 @@
+/* Copyright (C) 2018  Curtis McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sysexits.h>
+#include <time.h>
+
+#include "chat.h"
+
+static int logRoot = -1;
+
+static struct Log {
+	int dir;
+	int year;
+	int month;
+	int day;
+	FILE *file;
+} logs[TAGS_LEN];
+
+void logOpen(const char *path) {
+	logRoot = open(path, O_RDONLY | O_CLOEXEC);
+	if (logRoot < 0) err(EX_CANTCREAT, "%s", path);
+}
+
+static void sanitize(char *name) {
+	for (; name[0]; ++name) {
+		if (name[0] == '/') name[0] = '_';
+	}
+}
+
+static FILE *logFile(struct Tag tag, const struct tm *time) {
+	struct Log *log = &logs[tag.id];
+	if (
+		log->file
+		&& log->year == time->tm_year
+		&& log->month == time->tm_mon
+		&& log->day == time->tm_mday
+	) return log->file;
+
+	if (log->file) {
+		fclose(log->file);
+
+	} else {
+		char *name = strdup(tag.name);
+		if (!name) err(EX_OSERR, "strdup");
+		sanitize(name);
+
+		int error = mkdirat(logRoot, name, 0700);
+		if (error && errno != EEXIST) err(EX_CANTCREAT, "%s", name);
+
+		log->dir = openat(logRoot, name, O_RDONLY | O_CLOEXEC);
+		if (log->dir < 0) err(EX_CANTCREAT, "%s", name);
+
+		free(name);
+	}
+
+	log->year = time->tm_year;
+	log->month = time->tm_mon;
+	log->day = time->tm_mday;
+
+	char path[sizeof("YYYY-MM-DD.log")];
+	strftime(path, sizeof(path), "%F.log", time);
+	int fd = openat(
+		log->dir, path, O_WRONLY | O_APPEND | O_CREAT | O_CLOEXEC, 0700
+	);
+	if (fd < 0) err(EX_CANTCREAT, "%s/%s", tag.name, path);
+
+	log->file = fdopen(fd, "a");
+	if (!log->file) err(EX_CANTCREAT, "%s/%s", tag.name, path);
+	setlinebuf(log->file);
+
+	return log->file;
+}
+
+void logFmt(struct Tag tag, const time_t *ts, const char *format, ...) {
+	if (logRoot < 0) return;
+
+	time_t t;
+	if (!ts) {
+		t = time(NULL);
+		ts = &t;
+	}
+
+	struct tm *time = localtime(ts);
+	if (!time) err(EX_SOFTWARE, "localtime");
+
+	FILE *file = logFile(tag, time);
+
+	char stamp[sizeof("YYYY-MM-DDThh:mm:ss+hhmm")];
+	strftime(stamp, sizeof(stamp), "%FT%T%z", time);
+	fprintf(file, "[%s] ", stamp);
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+
+	va_list ap;
+	va_start(ap, format);
+	vfprintf(file, format, ap);
+	va_end(ap);
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+
+	fprintf(file, "\n");
+	if (ferror(file)) err(EX_IOERR, "%s", tag.name);
+}