diff --git a/controllers/threads_controller.go b/controllers/threads_controller.go
index 784f3a4..a7fde5e 100644
--- a/controllers/threads_controller.go
+++ b/controllers/threads_controller.go
@@ -125,6 +125,14 @@ func CreateThread(c *gin.Context) {
 	}
 
 	filesInRequest := form.File["files"]
+	isFilesSizesNotToBig := Utils.CheckFilesSize(filesInRequest)
+	if !isFilesSizesNotToBig {
+		errorHtmlData := Repositories.BadRequestHtmlData{
+			Message: Repositories.InvalidFileSizeMessage,
+		}
+		c.HTML(http.StatusInternalServerError, "400.html", errorHtmlData)
+		return
+	}
 
 	conn, err := Db.Pool.Acquire(context.TODO())
 	if err != nil {
@@ -249,6 +257,15 @@ func UpdateThread(c *gin.Context) {
 	}
 
 	filesInRequest := form.File["files"]
+	isFilesSizesNotToBig := Utils.CheckFilesSize(filesInRequest)
+	if !isFilesSizesNotToBig {
+		errorHtmlData := Repositories.BadRequestHtmlData{
+			Message: Repositories.InvalidFileSizeMessage,
+		}
+		c.HTML(http.StatusInternalServerError, "400.html", errorHtmlData)
+		return
+	}
+
 	isSageField := form.Value["sage"]
 	var isSageString string
 	if len(isSageField) != 0 {
diff --git a/repositories/structs.go b/repositories/structs.go
index b3c5e4e..541f08f 100644
--- a/repositories/structs.go
+++ b/repositories/structs.go
@@ -59,3 +59,4 @@ type BadRequestHtmlData struct {
 
 var InvalidTitleOrTextErrorMessage = "TITLE OR TEXT SHOULD NOT BE EMPTY"
 var InvalidCaptchaErrorMessage = "INVALID CAPTCHA"
+var InvalidFileSizeMessage = "FILE SIZE EXCIDED (3MB PER FILE)"
diff --git a/utils/utils.go b/utils/utils.go
index b407a20..96901bf 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -5,6 +5,7 @@ import (
 	"image"
 	"image/jpeg"
 	"image/png"
+	"mime/multipart"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -13,6 +14,7 @@ import (
 )
 
 var UPLOADS_DIR_PATH = "uploads"
+var FILE_SIZE_IN_BYTES = 3145728 // 3MB
 
 // Check dir existence.
 func CheckIfFolderExists(path string) bool {
@@ -63,12 +65,27 @@ func CreateThreadFolder(postID int) error {
 	return nil
 }
 
+// TODO: add files length check
 func ValidatePost(title, text string) bool {
 	return (title == "" && text != "") ||
 		(title != "" && text == "") ||
 		(title != "" && text != "")
 }
 
+func CheckFilesSize(files []*multipart.FileHeader) bool {
+	for _, file := range files {
+		if file.Size > int64(FILE_SIZE_IN_BYTES) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// func CheckFilesExt(){
+
+// }
+
 func MakeImageThumbnail(originalPath, ext string, threadID, fileID int) (*image.NRGBA, error) {
 	img, err := imaging.Open(originalPath, imaging.AutoOrientation(true))
 	if err != nil {