diff --git a/include/cosms-core/file.h b/include/cosms-core/file.h
index f609ff4..45fd495 100644
--- a/include/cosms-core/file.h
+++ b/include/cosms-core/file.h
@@ -23,7 +23,7 @@ typedef enum {
     COSMS_FILE_FAILED_TO_WRITE = -8,
 } CosmsFileError;
 
-CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned int *size);
-CosmsFileError cosms_core_file_write(const char *path, const char *content, unsigned int size, bool override);
+CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned long long *size);
+CosmsFileError cosms_core_file_write(const char *path, const char *content, unsigned long long size, bool override);
 
 #endif
diff --git a/src/file.c b/src/file.c
index b3673af..670eb5f 100644
--- a/src/file.c
+++ b/src/file.c
@@ -9,6 +9,7 @@
 #include "cosms-core/file.h"
 
 #include <stdlib.h>
+#include <stdint.h>
 
 #if defined(__GNUC__)
 #include <unistd.h>
@@ -16,9 +17,10 @@
 #include <sys/stat.h>
 #include <errno.h>
 #elif defined(_WIN32)
+#include <windows.h>
 #endif
 
-CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned int *size) {
+CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned long long *size) {
     #if defined(__GNUC__)
     int file = open(path, O_RDONLY);
     if (file == -1) {
@@ -55,7 +57,7 @@ CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned i
     while (remaining_bytes != 0) {
         int read_bytes = read(file, (*content) + (file_stat.st_size - remaining_bytes), remaining_bytes);
         if (read_bytes == -1) {
-            free(content);
+            free(*content);
             close(file);
             return COSMS_FILE_FAILED_TO_READ;
         }
@@ -65,12 +67,68 @@ CosmsFileError cosms_core_file_read(const char *path, char **content, unsigned i
     
     close(file);
     #elif defined(_WIN32)
+    HANDLE file = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (file == INVALID_HANDLE_VALUE) {
+        switch(GetLastError()) {
+            case ERROR_FILE_NOT_FOUND:
+            case ERROR_PATH_NOT_FOUND:
+                return COSMS_FILE_NOT_FOUND;
+
+            case ERROR_ACCESS_DENIED:
+            case ERROR_SHARING_VIOLATION:
+            case ERROR_LOCK_VIOLATION:
+                return COSMS_FILE_NO_ACCESS;
+
+            case ERROR_TOO_MANY_OPEN_FILES:
+                return COSMS_FILE_LIMIT_REACHED;
+
+            default:
+                return COSMS_FILE_UNKOWN_ERROR;
+        }
+    }
+
+    DWORD high_size;
+    DWORD low_size = GetFileSize(file, &high_size);
+    if (low_size == INVALID_FILE_SIZE && GetLastError() != NO_ERROR) {
+        CloseHandle(file);
+        return COSMS_FILE_COULD_NOT_READ_SIZE;
+    }
+
+    unsigned long long file_size = ((unsigned long long)high_size << 32) | low_size;
+
+    *size = file_size;
+    *content = (char*)malloc((file_size + 1) * sizeof(char));
+    if (content == NULL) {
+        CloseHandle(file);
+        return COSMS_FILE_FAILED_TO_ALLOCATE;
+    }
+
+    unsigned long long remaining_bytes = file_size;
+    while (remaining_bytes != 0) {
+        DWORD bytes_to_read, read_bytes;
+        if (remaining_bytes > UINT_MAX) {
+            bytes_to_read = UINT_MAX;
+        } else {
+            bytes_to_read = (DWORD)remaining_bytes;
+        }
+
+        if (!ReadFile(file, (*content) + (file_size - remaining_bytes), bytes_to_read, &read_bytes, NULL)) {
+            free(*content);
+            CloseHandle(file);
+            return COSMS_FILE_FAILED_TO_READ;
+        }
+
+        remaining_bytes -= read_bytes;
+    }
+
+    (*content)[file_size] = '\0';
+    CloseHandle(file);
     #endif
 
     return COSMS_FILE_OK;
 }
 
-CosmsFileError cosms_core_file_write(const char *path, const char *content, unsigned int size, bool override) {
+CosmsFileError cosms_core_file_write(const char *path, const char *content, unsigned long long size, bool override) {
     #if defined(__GNUC__)
     int file;
     if (override) {
@@ -109,6 +167,50 @@ CosmsFileError cosms_core_file_write(const char *path, const char *content, unsi
 
     close(file);
     #elif defined(_WIN32)
+    HANDLE file;
+    if (override) {
+        file = CreateFile(path, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    } else {
+        file = CreateFile(path, FILE_APPEND_DATA, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    }
+
+    if (file == INVALID_HANDLE_VALUE) {
+        switch(GetLastError()) {
+            case ERROR_FILE_NOT_FOUND:
+            case ERROR_PATH_NOT_FOUND:
+                return COSMS_FILE_NOT_FOUND;
+
+            case ERROR_ACCESS_DENIED:
+            case ERROR_SHARING_VIOLATION:
+            case ERROR_LOCK_VIOLATION:
+                return COSMS_FILE_NO_ACCESS;
+
+            case ERROR_TOO_MANY_OPEN_FILES:
+                return COSMS_FILE_LIMIT_REACHED;
+
+            default:
+                return COSMS_FILE_UNKOWN_ERROR;
+        }
+    }
+
+    unsigned long long remaining_bytes = size;
+    while (remaining_bytes != 0) {
+        DWORD bytes_to_write, written_bytes;
+        if (remaining_bytes > UINT_MAX) {
+            bytes_to_write = UINT_MAX;
+        } else {
+            bytes_to_write = (DWORD)remaining_bytes;
+        }
+
+        if (!WriteFile(file, content + (size - remaining_bytes), bytes_to_write, &written_bytes, NULL)) {
+            CloseHandle(file);
+            return COSMS_FILE_FAILED_TO_WRITE;
+        }
+
+        remaining_bytes -= written_bytes;
+    }
+
+    CloseHandle(file);
     #endif
 
     return COSMS_FILE_OK;
diff --git a/tests/main.c b/tests/main.c
index b63a90b..0b3de1d 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -3,7 +3,7 @@
 #include <stdio.h>
 
 int main(void) {
-    unsigned int buffer_size;
+    unsigned long long buffer_size;
     char *buffer;
 	CosmsFileError error = cosms_core_file_read("test.txt", &buffer, &buffer_size);
     if (error != COSMS_FILE_OK) {
@@ -11,7 +11,7 @@ int main(void) {
         return -1;
     }
 
-    printf("File read with content:\n %s\n", buffer);
+    printf("File read with content:\n%s\n", buffer);
 
     char *temp_buffer = "Hello, World!";
     error = cosms_core_file_write("write-file.txt", temp_buffer, 13, true);