diff --git a/bmp.c b/bmp.c
index ee53821237..c2bd91270f 100644
--- a/bmp.c
+++ b/bmp.c
@@ -15,7 +15,7 @@ void BmpInitializeBuffer(BmpBuffer *buffer, FILE *file) {
 
 static inline void AdvanceBuffer(BmpBuffer *buffer)
 {
-	buffer->read = fread(buffer->data, 1, BMP_BUFFER_SIZE, buffer->file);
+	buffer->read = (int)fread(buffer->data, 1, BMP_BUFFER_SIZE, buffer->file);
 	buffer->pos  = 0;
 }
 
diff --git a/console.c b/console.c
index 6dbbe803d1..5c7eadf937 100644
--- a/console.c
+++ b/console.c
@@ -680,7 +680,7 @@ IConsoleAlias *IConsoleAliasGet(const char *name)
 /** copy in an argument into the aliasstream */
 static inline int IConsoleCopyInParams(char *dst, const char *src, uint bufpos)
 {
-	int len = min(ICON_MAX_STREAMSIZE - bufpos, strlen(src));
+	int len = min(ICON_MAX_STREAMSIZE - bufpos, (int)strlen(src));
 	strncpy(dst, src, len);
 
 	return len;
diff --git a/misc.c b/misc.c
index c74b68055f..e18db9bb1f 100644
--- a/misc.c
+++ b/misc.c
@@ -253,7 +253,7 @@ static void Save_NAME(void)
 	for (i = 0; i != lengthof(_name_array); ++i) {
 		if (_name_array[i][0] != '\0') {
 			SlSetArrayIndex(i);
-			SlArray(_name_array[i], strlen(_name_array[i]), SLE_UINT8);
+			SlArray(_name_array[i], (uint)strlen(_name_array[i]), SLE_UINT8);
 		}
 	}
 }
diff --git a/namegen.c b/namegen.c
index 44e3474521..92c471d1c3 100644
--- a/namegen.c
+++ b/namegen.c
@@ -475,7 +475,7 @@ static byte MakeCzechTownName(char *buf, uint32 seed)
 
 	if (do_prefix) {
 		CzechPattern pattern = name_czech_adj[prefix].pattern;
-		int endpos;
+		size_t endpos;
 
 		strcat(buf, name_czech_adj[prefix].name);
 		endpos = strlen(buf) - 1;
@@ -496,7 +496,7 @@ static byte MakeCzechTownName(char *buf, uint32 seed)
 		if (postfix < lengthof(name_czech_subst_postfix)) {
 			const char *poststr = name_czech_subst_postfix[postfix];
 			const char *endstr = name_czech_subst_ending[ending].name;
-			int postlen, endlen;
+			size_t postlen, endlen;
 
 			postlen = strlen(poststr);
 			endlen = strlen(endstr);
@@ -507,7 +507,7 @@ static byte MakeCzechTownName(char *buf, uint32 seed)
 						(poststr[1] != 'v' || poststr[1] != endstr[1]) &&
 						poststr[2] != endstr[1])
 					) {
-				uint buflen;
+				size_t buflen;
 				strcat(buf, poststr);
 				buflen = strlen(buf);
 
diff --git a/network_server.c b/network_server.c
index 9a3c649306..b4e05f9406 100644
--- a/network_server.c
+++ b/network_server.c
@@ -313,7 +313,7 @@ DEF_SERVER_SEND_COMMAND(PACKET_SERVER_MAP)
 		for (i = 0; i < sent_packets; i++) {
 			Packet *p = NetworkSend_Init(PACKET_SERVER_MAP);
 			NetworkSend_uint8(p, MAP_PACKET_NORMAL);
-			res = fread(p->buffer + p->size, 1, SEND_MTU - p->size, file_pointer);
+			res = (int)fread(p->buffer + p->size, 1, SEND_MTU - p->size, file_pointer);
 			if (ferror(file_pointer)) {
 				error("Error reading temporary network savegame!");
 			}
diff --git a/newgrf.c b/newgrf.c
index 5d557f2166..27a31e6089 100644
--- a/newgrf.c
+++ b/newgrf.c
@@ -1876,7 +1876,7 @@ static void FeatureNewName(byte *buf, int len)
 			}
 		}
 		name += ofs;
-		len -= ofs;
+		len -= (int)ofs;
 	}
 }
 
diff --git a/oldloader.c b/oldloader.c
index 6bdea4f09f..ce3a78d1d4 100644
--- a/oldloader.c
+++ b/oldloader.c
@@ -120,7 +120,7 @@ static byte ReadByteFromFile(LoadgameState *ls)
 	and just return a byte per time */
 	if (ls->buffer_cur >= ls->buffer_count) {
 		/* Read some new bytes from the file */
-		int count = fread(ls->buffer, 1, BUFFER_SIZE, ls->file);
+		int count = (int)fread(ls->buffer, 1, BUFFER_SIZE, ls->file);
 
 		/* We tried to read, but there is nothing in the file anymore.. */
 		if (count == 0) {
@@ -376,7 +376,7 @@ static void FixOldVehicles(void)
  *  - OCL_CHUNK: load an other proc to load a part of the savegame, 'amount' times
  *  - OCL_ASSERT: to check if we are really at the place we expect to be.. because old savegames are too binary to be sure ;)
  */
-#define OCL_SVAR(type, base, offset)         { type,          1, NULL,    offsetof(base, offset), NULL }
+#define OCL_SVAR(type, base, offset)         { type,          1, NULL,    (uint)offsetof(base, offset), NULL }
 #define OCL_VAR(type, amount, pointer)       { type,     amount, pointer, 0,                      NULL }
 #define OCL_END()                                   { OC_END,        0, NULL,    0,                      NULL }
 #define OCL_NULL(amount)                            { OC_NULL,  amount, NULL,    0,                      NULL }
diff --git a/players.c b/players.c
index 8e96393da8..d27477c4d3 100644
--- a/players.c
+++ b/players.c
@@ -1065,7 +1065,7 @@ void SaveToHighScore(void)
 		for (i = 0; i < LAST_HS_ITEM; i++) { // don't save network highscores
 			for (hs = _highscore_table[i]; hs != endof(_highscore_table[i]); hs++) {
 				/* First character is a command character, so strlen will fail on that */
-				byte length = min(sizeof(hs->company), (hs->company[0] == '\0') ? 0 : strlen(&hs->company[1]) + 1);
+				byte length = min(sizeof(hs->company), (hs->company[0] == '\0') ? 0 : (int)strlen(&hs->company[1]) + 1);
 
 				fwrite(&length, sizeof(length), 1, fp); // write away string length
 				fwrite(hs->company, length, 1, fp);
diff --git a/spritecache.c b/spritecache.c
index 8e99a34f44..9fe087f997 100644
--- a/spritecache.c
+++ b/spritecache.c
@@ -192,7 +192,7 @@ static inline MemBlock* NextBlock(MemBlock* block)
 
 static uint32 GetSpriteCacheUsage(void)
 {
-	size_t tot_size = 0;
+	uint32 tot_size = 0;
 	MemBlock* s;
 
 	for (s = _spritecache_ptr; s->size != 0; s = NextBlock(s))
diff --git a/strings.c b/strings.c
index 89c2b4a1ce..6945d94433 100644
--- a/strings.c
+++ b/strings.c
@@ -1229,7 +1229,7 @@ void InitializeLanguagePacks(void)
 
 	// go through the language files and make sure that they are valid.
 	for (i = m = 0; i != n; i++) {
-		int j;
+		size_t j;
 
 		char *s = str_fmt("%s%s", _path.lang_dir, files[i]);
 		in = fopen(s, "rb");
diff --git a/win32.c b/win32.c
index 099cc8f98f..48c50027cd 100644
--- a/win32.c
+++ b/win32.c
@@ -265,7 +265,7 @@ static const char *SubmitCrashReport(HWND wnd, void *msg, size_t msglen, const c
 	http = _wininet.HttpOpenRequest(conn, "POST", buff, NULL, NULL, NULL, INTERNET_FLAG_NO_CACHE_WRITE , 0);
 	if (http == NULL) { err = "httpopenrequest failed"; goto error3; }
 
-	if (!_wininet.HttpSendRequest(http, "Content-type: application/binary", -1, msg, msglen)) { err = "httpsendrequest failed"; goto error4; }
+	if (!_wininet.HttpSendRequest(http, "Content-type: application/binary", -1, msg, (DWORD)msglen)) { err = "httpsendrequest failed"; goto error4; }
 
 	len = sizeof(code);
 	if (!_wininet.HttpQueryInfo(http, HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER, &code, &len, 0)) { err = "httpqueryinfo failed"; goto error4; }