diff --git a/src/common/cfgfiles.c b/src/common/cfgfiles.c
index 8ed31c4f..5de72dbd 100644
--- a/src/common/cfgfiles.c
+++ b/src/common/cfgfiles.c
@@ -207,10 +207,10 @@ cfg_get_str (char *cfg, const char *var, char *dest, int dest_len)
 		while (*cfg != 0 && *cfg != '\n')
 			cfg++;
 		if (*cfg == 0)
-			return 0;
+			return NULL;
 		cfg++;
 		if (*cfg == 0)
-			return 0;
+			return NULL;
 	}
 }
 
diff --git a/src/common/dcc.c b/src/common/dcc.c
index 8c6396b3..97cd5f14 100644
--- a/src/common/dcc.c
+++ b/src/common/dcc.c
@@ -494,7 +494,7 @@ dcc_write_chat (char *nick, char *text)
 		fe_dcc_update (dcc);
 		return dcc;
 	}
-	return 0;
+	return NULL;
 }
 
 /* returns: 0 - ok
@@ -1936,7 +1936,7 @@ find_dcc_from_id (int id, int type)
 		return dcc;
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 static struct DCC *
@@ -1952,7 +1952,7 @@ find_dcc_from_port (int port, int type)
 			return dcc;
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 struct DCC *
@@ -1977,7 +1977,7 @@ find_dcc (char *nick, char *file, int type)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 /* called when we receive a NICK change from server */
diff --git a/src/common/hexchat.c b/src/common/hexchat.c
index fdae21d0..7d8e462f 100644
--- a/src/common/hexchat.c
+++ b/src/common/hexchat.c
@@ -209,7 +209,7 @@ find_dialog (server *serv, char *nick)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 session *
@@ -227,7 +227,7 @@ find_channel (server *serv, char *chan)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 static void
diff --git a/src/common/history.c b/src/common/history.c
index 34924568..23a8463e 100644
--- a/src/common/history.c
+++ b/src/common/history.c
@@ -52,7 +52,7 @@ history_down (struct history *his)
 	int next;
 
 	if (his->pos == his->realpos)	/* allow down only after up */
-		return 0;
+		return NULL;
 	if (his->realpos == 0)
 	{
 		if (his->pos == HISTORY_SIZE - 1)
@@ -79,7 +79,7 @@ history_down (struct history *his)
 		return his->lines[his->pos];
 	}
 
-	return 0;
+	return NULL;
 }
 
 char *
@@ -90,11 +90,11 @@ history_up (struct history *his, char *current_text)
 	if (his->realpos == HISTORY_SIZE - 1)
 	{
 		if (his->pos == 0)
-			return 0;
+			return NULL;
 	} else
 	{
 		if (his->pos == his->realpos + 1)
-			return 0;
+			return NULL;
 	}
 
 	next = HISTORY_SIZE - 1;
@@ -117,5 +117,5 @@ history_up (struct history *his, char *current_text)
 		return his->lines[his->pos];
 	}
 
-	return 0;
+	return NULL;
 }
diff --git a/src/common/inbound.c b/src/common/inbound.c
index 720c7e9b..db68c64c 100644
--- a/src/common/inbound.c
+++ b/src/common/inbound.c
@@ -118,7 +118,7 @@ find_session_from_nick (char *nick, server *serv)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 static session *
@@ -555,7 +555,7 @@ find_unused_session (server *serv)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 static session *
@@ -573,7 +573,7 @@ find_session_from_waitchannel (char *chan, struct server *serv)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 void
@@ -932,7 +932,7 @@ find_session_from_type (int type, server *serv)
 			return sess;
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 void
diff --git a/src/common/notify.c b/src/common/notify.c
index b7c56573..b5316c36 100644
--- a/src/common/notify.c
+++ b/src/common/notify.c
@@ -196,7 +196,7 @@ notify_find (server *serv, char *nick)
 		list = list->next;
 	}
 
-	return 0;
+	return NULL;
 }
 
 static void
diff --git a/src/common/outbound.c b/src/common/outbound.c
index 0df9c37c..fab573e4 100644
--- a/src/common/outbound.c
+++ b/src/common/outbound.c
@@ -1654,7 +1654,7 @@ memrchr (const void *block, int c, size_t size)
 	for (p = (unsigned char *)block + size; p != block; p--)
 		if (*p == c)
 			return p;
-	return 0;
+	return NULL;
 }
 #endif
 
diff --git a/src/common/userlist.c b/src/common/userlist.c
index aa0f8f16..54ed6f03 100644
--- a/src/common/userlist.c
+++ b/src/common/userlist.c
@@ -221,7 +221,7 @@ userlist_find_global (struct server *serv, char *name)
 		}
 		list = list->next;
 	}
-	return 0;
+	return NULL;
 }
 
 static void
diff --git a/src/fe-gtk/xtext.c b/src/fe-gtk/xtext.c
index 57b98cc6..495568f8 100644
--- a/src/fe-gtk/xtext.c
+++ b/src/fe-gtk/xtext.c
@@ -951,7 +951,7 @@ gtk_xtext_find_char (GtkXText * xtext, int x, int y, int *off,
 	line = (y + xtext->pixel_offset) / xtext->fontsize;
 	ent = gtk_xtext_nth (xtext, line + (int)xtext->adj->value, &subline);
 	if (!ent)
-		return 0;
+		return NULL;
 
 	if (off)
 		*off = gtk_xtext_find_x (xtext, x, ent, subline, line, out_of_bounds);
@@ -1588,11 +1588,11 @@ gtk_xtext_get_word (GtkXText * xtext, int x, int y, textentry ** ret_ent,
 
 		/* make sure we're not before the start of the match */
 		if (len_to_offset < start)
-			return 0;
+			return NULL;
 
 		/* and not after it */
 		if (len_to_offset - start >= end - start)
-			return 0;
+			return NULL;
 	}
 
 	return word;
@@ -3646,7 +3646,7 @@ gtk_xtext_nth (GtkXText *xtext, int line, int *subline)
 					break;
 				lines -= g_slist_length (ent->sublines);
 			}
-			return 0;
+			return NULL;
 		}
 	}
 	/* -- end of optimization -- */
@@ -3661,7 +3661,7 @@ gtk_xtext_nth (GtkXText *xtext, int line, int *subline)
 		}
 		ent = ent->next;
 	}
-	return 0;
+	return NULL;
 }
 
 /* render enta (or an inclusive range enta->entb) */