diff --git a/cmd/config.go b/cmd/config.go
index 4c194ae..70e785b 100644
--- a/cmd/config.go
+++ b/cmd/config.go
@@ -3,6 +3,7 @@ package cmd
 import (
 	"fmt"
 	"net/url"
+	"os"
 	"sort"
 	"strings"
 	"time"
@@ -30,6 +31,7 @@ type RunConfig struct {
 	Duration     time.Duration
 	Method       string
 	Body         string
+	BodyFile     string
 	Headers      []string
 	Verbose      bool
 }
@@ -58,6 +60,17 @@ func (c *RunConfig) Validate() error {
 	}
 	c.ParsedTarget = u
 
+	if c.BodyFile != "" {
+		if c.Body != "" {
+			return fmt.Errorf("cannot use both -b (body string) and -D (body file)")
+		}
+		data, err := os.ReadFile(c.BodyFile)
+		if err != nil {
+			return fmt.Errorf("failed to read body file %q: %w", c.BodyFile, err)
+		}
+		c.Body = string(data)
+	}
+
 	if c.Concurrency <= 0 {
 		return fmt.Errorf("concurrency must be positive, got %d", c.Concurrency)
 	}
diff --git a/cmd/config_test.go b/cmd/config_test.go
index a435321..aae9b59 100644
--- a/cmd/config_test.go
+++ b/cmd/config_test.go
@@ -1,6 +1,8 @@
 package cmd
 
 import (
+	"os"
+	"strings"
 	"testing"
 	"time"
 
@@ -8,6 +10,20 @@ import (
 )
 
 func TestRunConfig_Validate(t *testing.T) {
+	tmpFile, err := os.CreateTemp("", "body*.txt")
+	if err != nil {
+		t.Fatalf("failed to create temp file: %v", err)
+	}
+	defer func() {
+		_ = os.Remove(tmpFile.Name())
+	}()
+	if _, err := tmpFile.Write([]byte("hello file body")); err != nil {
+		t.Fatalf("failed to write temp file: %v", err)
+	}
+	if err := tmpFile.Close(); err != nil {
+		t.Fatalf("failed to close temp file: %v", err)
+	}
+
 	validConfig := func() RunConfig {
 		return RunConfig{
 			Target:      "https://example.com/api",
@@ -25,6 +41,7 @@ func TestRunConfig_Validate(t *testing.T) {
 		mutate  func(*RunConfig)
 		wantErr bool
 		errMsg  string
+		check   func(*testing.T, *RunConfig)
 	}{
 		{
 			name:    "Valid configuration",
@@ -225,6 +242,35 @@ func TestRunConfig_Validate(t *testing.T) {
 			wantErr: true,
 			errMsg:  `invalid header format ": some-value", expected 'Key: Value' without spaces in the key`,
 		},
+		{
+			name: "Both body and body file set",
+			mutate: func(c *RunConfig) {
+				c.Body = "some body text"
+				c.BodyFile = "some_file.txt"
+			},
+			wantErr: true,
+			errMsg:  "cannot use both -b (body string) and -D (body file)",
+		},
+		{
+			name: "Nonexistent body file",
+			mutate: func(c *RunConfig) {
+				c.BodyFile = "does_not_exist_12345.txt"
+			},
+			wantErr: true,
+			errMsg:  "failed to read body file \"does_not_exist_12345.txt\"",
+		},
+		{
+			name: "Valid body file",
+			mutate: func(c *RunConfig) {
+				c.BodyFile = tmpFile.Name()
+			},
+			wantErr: false,
+			check: func(t *testing.T, c *RunConfig) {
+				if c.Body != "hello file body" {
+					t.Errorf("expected Body to be %q, got %q", "hello file body", c.Body)
+				}
+			},
+		},
 	}
 
 	for _, tt := range tests {
@@ -236,7 +282,7 @@ func TestRunConfig_Validate(t *testing.T) {
 			if tt.wantErr {
 				if err == nil {
 					t.Errorf("expected error but got nil")
-				} else if tt.errMsg != "" && err.Error() != tt.errMsg {
+				} else if tt.errMsg != "" && !strings.Contains(err.Error(), tt.errMsg) {
 					t.Errorf("expected error containing %q, got %q", tt.errMsg, err.Error())
 				}
 			} else {
@@ -244,6 +290,10 @@ func TestRunConfig_Validate(t *testing.T) {
 					t.Errorf("unexpected error: %v", err)
 				}
 			}
+
+			if tt.check != nil {
+				tt.check(t, &cfg)
+			}
 		})
 	}
 }
diff --git a/cmd/configfile.go b/cmd/configfile.go
index af90101..d7abe00 100644
--- a/cmd/configfile.go
+++ b/cmd/configfile.go
@@ -20,6 +20,7 @@ type fileConfig struct {
 	Duration    *string  `json:"duration" yaml:"duration"`
 	Method      *string  `json:"method" yaml:"method"`
 	Body        *string  `json:"body" yaml:"body"`
+	BodyFile    *string  `json:"body_file" yaml:"body_file"`
 	Headers     []string `json:"headers" yaml:"headers"`
 	Verbose     *bool    `json:"verbose" yaml:"verbose"`
 }
@@ -116,6 +117,10 @@ func mergeConfig(file *fileConfig, cli RunConfig, changed map[string]bool) (RunC
 		merged.Body = *file.Body
 	}
 
+	if file.BodyFile != nil && !changed["body-file"] {
+		merged.BodyFile = *file.BodyFile
+	}
+
 	if len(file.Headers) > 0 && !changed["header"] {
 		merged.Headers = make([]string, len(file.Headers))
 		copy(merged.Headers, file.Headers)
diff --git a/cmd/run.go b/cmd/run.go
index 1447376..4621ced 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -54,6 +54,7 @@ Latency Percentiles:
 			duration, _ := f.GetDuration("duration")
 			method, _ := f.GetString("method")
 			body, _ := f.GetString("body")
+			bodyFile, _ := f.GetString("body-file")
 			headers, _ := f.GetStringArray("header")
 			verbose, _ := f.GetBool("verbose")
 			outputFormat, _ := f.GetString("output")
@@ -75,6 +76,7 @@ Latency Percentiles:
 				Duration:    duration,
 				Method:      strings.ToUpper(method),
 				Body:        body,
+				BodyFile:    bodyFile,
 				Headers:     headers,
 				Verbose:     verbose,
 			}
@@ -135,6 +137,7 @@ Latency Percentiles:
 	cmd.Flags().DurationP("duration", "d", 0, "Duration to run the test. Overrides -n when set (e.g., 10s, 1m)")
 	cmd.Flags().StringP("method", "m", "GET", "HTTP method to use")
 	cmd.Flags().StringP("body", "b", "", "Request body content")
+	cmd.Flags().StringP("body-file", "D", "", "Path to file containing the request body")
 	cmd.Flags().StringArrayP("header", "H", []string{}, "HTTP header in 'Key: Value' format (can be repeated)")
 	cmd.Flags().StringP("config", "f", "", "Path to configuration file (JSON/YAML)")
 	cmd.Flags().BoolP("verbose", "v", false, "Enable verbose output")