diff --git a/Cargo.lock b/Cargo.lock
index a7d341b..1f1de34 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -196,6 +196,16 @@ version = "0.8.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "248e3bacc7dc6baa3b21e405ee045c3047101a49145e7e9eca583ab4c2ca5345"
 
+[[package]]
+name = "cruet"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6132609543972496bc97b1e01f1ce6586768870aeb4cabeb3385f4e05b5caead"
+dependencies = [
+ "once_cell",
+ "regex",
+]
+
 [[package]]
 name = "cucumber"
 version = "0.20.2"
@@ -272,6 +282,7 @@ name = "dev_case"
 version = "0.1.0"
 dependencies = [
  "clap",
+ "cruet",
  "cucumber",
  "futures",
  "regex",
diff --git a/Cargo.toml b/Cargo.toml
index 6dcf58d..2b53e87 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.4", features = ["derive"] }
+cruet = "0.14.0"
 regex = "1.10.4"
 
 [dev-dependencies]
diff --git a/src/lib.rs b/src/lib.rs
index 3da331f..ee75c56 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,9 +1,23 @@
 use regex::Regex;
 
+fn concert_replacement(original: &str, replacement: &str) -> String {
+    if cruet::is_camel_case(original) {
+        cruet::to_camel_case(replacement)
+    } else if cruet::is_kebab_case(original) {
+        cruet::to_kebab_case(replacement)
+    } else if cruet::is_pascal_case(original) {
+        cruet::to_pascal_case(replacement)
+    } else if cruet::is_snake_case(original) {
+        cruet::to_snake_case(replacement)
+    } else {
+        replacement.to_string()
+    }
+}
+
 pub fn replace(search: &String, replace: String, input: String) -> String {
     let mut index = 0;
     let mut output = input;
-    let search_pattern = Regex::new(search).unwrap();
+    let search_pattern = Regex::new(&format!("(?i){search}")).unwrap();
 
     while let Some(search_match) = search_pattern.find_at(&output, index) {
         let start = search_match.start();
@@ -19,8 +33,10 @@ pub fn replace(search: &String, replace: String, input: String) -> String {
             }
         };
 
-        index = start + replacement.len();
-        output.replace_range(start..end, &replacement);
+        let converted_replacement = concert_replacement(&output[start..end], &replacement);
+        output.replace_range(start..end, &converted_replacement);
+
+        index = start + converted_replacement.len();
     }
 
     output
diff --git a/tests/features/case-perserving.feature b/tests/features/case-perserving.feature
new file mode 100644
index 0000000..00a3655
--- /dev/null
+++ b/tests/features/case-perserving.feature
@@ -0,0 +1,7 @@
+Feature: Case preserving search and replace
+
+  Scenario: You can search and replace with with a regular expression
+    Given Search is 'productid'
+    And Replace is 'catalogId'
+    And Input is 'function GetProductId(productId)'
+    Then Output is 'function GetCatalogId(catalogId)'
diff --git a/tests/features/regex.feature b/tests/features/regex.feature
index cc77786..0e07ec5 100644
--- a/tests/features/regex.feature
+++ b/tests/features/regex.feature
@@ -3,7 +3,7 @@ Feature: Regex search and replace
   Scenario: You can search and replace with with a regular expression
     Given Search is '(\w+)'
     And Replace is 'new'
-    And Input is 'This is a'
+    And Input is 'this is a'
     Then Output is 'new new new'
 
   Scenario: You can use a '$' to replace a match group