diff --git a/src/main.rs b/src/main.rs
index f9d15a9..2efcb61 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,6 +12,9 @@ struct Cli {
 
     #[arg(value_name = "FILES", num_args = 1..)]
     file_paths: Vec<PathBuf>,
+
+    #[arg(short, long)]
+    ignore_case: bool,
 }
 
 fn main() -> ExitCode {
@@ -33,7 +36,7 @@ fn run() -> anyhow::Result<Matches> {
 
     // println!("{:?} {}", cli.file_paths, cli.pattern);
 
-    let matches = process_files(&cli.file_paths, &cli.pattern)?;
+    let matches = process_files(&cli.file_paths, &cli.pattern, &cli)?;
 
     Ok(matches)
 }
diff --git a/src/parser.rs b/src/parser.rs
index 6bbd9b3..cab8874 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -5,19 +5,23 @@ use std::{
 };
 
 use anyhow::Context;
-use regex::Regex;
+use regex::{Regex, RegexBuilder};
 
-use crate::matches::{Match, Matches};
+use crate::{
+    matches::{Match, Matches},
+    Cli,
+};
 
 pub fn process_files(
     file_paths: &Vec<PathBuf>,
     pattern: &str,
+    cli: &Cli,
 ) -> anyhow::Result<Matches, anyhow::Error> {
     let mut matches = Matches { items: vec![], pattern: String::from(pattern) };
 
     for file_path in file_paths {
         let lines_iter = read_lines(file_path)?;
-        let mut _matches = match_pattern(lines_iter, pattern, file_path)?;
+        let mut _matches = match_pattern(lines_iter, pattern, file_path, cli)?;
         matches.append(&mut _matches);
     }
 
@@ -56,8 +60,13 @@ pub fn match_pattern(
     iter: impl Iterator<Item = std::io::Result<String>>,
     pattern: &str,
     file_path: &Path,
+    cli: &Cli,
 ) -> anyhow::Result<Matches, anyhow::Error> {
-    let reg = Regex::new(pattern).with_context(|| format!("invalid regex: {:?}", pattern))?;
+    let reg = RegexBuilder::new(pattern)
+        .case_insensitive(cli.ignore_case)
+        .build()
+        .with_context(|| format!("invalid regex: {:?}", pattern))?;
+
     let mut matches = Vec::new();
 
     for (idx, line) in iter.enumerate() {