diff --git a/src/core/ngx_slab.c b/src/core/ngx_slab.c
index 66faecc74..1d4ce2b67 100644
--- a/src/core/ngx_slab.c
+++ b/src/core/ngx_slab.c
@@ -101,7 +101,7 @@ ngx_slab_init(ngx_slab_pool_t *pool)
     }
     /**/
 
-    pool->min_size = 1 << pool->min_shift;
+    pool->min_size = (size_t) 1 << pool->min_shift;
 
     slots = ngx_slab_slots(pool);
 
@@ -473,7 +473,7 @@ ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
     case NGX_SLAB_SMALL:
 
         shift = slab & NGX_SLAB_SHIFT_MASK;
-        size = 1 << shift;
+        size = (size_t) 1 << shift;
 
         if ((uintptr_t) p & (size - 1)) {
             goto wrong_chunk;
@@ -568,7 +568,7 @@ ngx_slab_free_locked(ngx_slab_pool_t *pool, void *p)
     case NGX_SLAB_BIG:
 
         shift = slab & NGX_SLAB_SHIFT_MASK;
-        size = 1 << shift;
+        size = (size_t) 1 << shift;
 
         if ((uintptr_t) p & (size - 1)) {
             goto wrong_chunk;
diff --git a/src/http/ngx_http_script.c b/src/http/ngx_http_script.c
index c2b165801..c1a0b4c56 100644
--- a/src/http/ngx_http_script.c
+++ b/src/http/ngx_http_script.c
@@ -356,11 +356,11 @@ ngx_http_script_compile(ngx_http_script_compile_t *sc)
 
                 n = sc->source->data[i] - '0';
 
-                if (sc->captures_mask & (1 << n)) {
+                if (sc->captures_mask & ((ngx_uint_t) 1 << n)) {
                     sc->dup_capture = 1;
                 }
 
-                sc->captures_mask |= 1 << n;
+                sc->captures_mask |= (ngx_uint_t) 1 << n;
 
                 if (ngx_http_script_add_capture_code(sc, n) != NGX_OK) {
                     return NGX_ERROR;
diff --git a/src/http/ngx_http_script.h b/src/http/ngx_http_script.h
index 46592ab01..a5116d747 100644
--- a/src/http/ngx_http_script.h
+++ b/src/http/ngx_http_script.h
@@ -121,16 +121,16 @@ typedef struct {
     uintptr_t                   status;
     uintptr_t                   next;
 
-    uintptr_t                   test:1;
-    uintptr_t                   negative_test:1;
-    uintptr_t                   uri:1;
-    uintptr_t                   args:1;
+    unsigned                    test:1;
+    unsigned                    negative_test:1;
+    unsigned                    uri:1;
+    unsigned                    args:1;
 
     /* add the r->args to the new arguments */
-    uintptr_t                   add_args:1;
+    unsigned                    add_args:1;
 
-    uintptr_t                   redirect:1;
-    uintptr_t                   break_cycle:1;
+    unsigned                    redirect:1;
+    unsigned                    break_cycle:1;
 
     ngx_str_t                   name;
 } ngx_http_script_regex_code_t;
@@ -139,13 +139,13 @@ typedef struct {
 typedef struct {
     ngx_http_script_code_pt     code;
 
-    uintptr_t                   uri:1;
-    uintptr_t                   args:1;
+    unsigned                    uri:1;
+    unsigned                    args:1;
 
     /* add the r->args to the new arguments */
-    uintptr_t                   add_args:1;
+    unsigned                    add_args:1;
 
-    uintptr_t                   redirect:1;
+    unsigned                    redirect:1;
 } ngx_http_script_regex_end_code_t;
 
 #endif
diff --git a/src/os/win32/ngx_win32_config.h b/src/os/win32/ngx_win32_config.h
index c5e26dcbd..3897730a1 100644
--- a/src/os/win32/ngx_win32_config.h
+++ b/src/os/win32/ngx_win32_config.h
@@ -94,6 +94,12 @@ typedef long  time_t;
 /* FD_SET() and FD_CLR(): conditional expression is constant */
 #pragma warning(disable:4127)
 
+/* conversion from 'type1' to 'type2', possible loss of data */
+#pragma warning(disable:4244)
+
+/* conversion from 'size_t' to 'type', possible loss of data */
+#pragma warning(disable:4267)
+
 /* array is too small to include a terminating null character */
 #pragma warning(disable:4295)
 
@@ -189,8 +195,12 @@ typedef unsigned int        ino_t;
 
 
 #ifndef __GNUC__
+#ifdef _WIN64
+typedef __int64             ssize_t;
+#else
 typedef int                 ssize_t;
 #endif
+#endif
 
 
 typedef uint32_t            in_addr_t;