diff --git a/zio-http/src/main/scala/zio/http/FormField.scala b/zio-http/src/main/scala/zio/http/FormField.scala
index ce880129b7..3d059f9a3a 100644
--- a/zio-http/src/main/scala/zio/http/FormField.scala
+++ b/zio-http/src/main/scala/zio/http/FormField.scala
@@ -175,7 +175,7 @@ object FormField {
       contentParts     = extract._4.tail // Skip the first empty line
       content          = contentParts.foldLeft(Chunk.empty[Byte])(_ ++ _.bytes)
       contentType      = extract._2
-        .flatMap(x => MediaType.forContentType(x.preposition))
+        .flatMap(x => MediaType.forContentType(x.value))
         .getOrElse(MediaType.application.`octet-stream`)
       transferEncoding = extract._3
         .flatMap(x => ContentTransferEncoding.parse(x.preposition).toOption)
@@ -190,7 +190,7 @@ object FormField {
     ast.collectFirst {
       case header: FormAST.Header if header.name == "Content-Type" =>
         MediaType
-          .forContentType(header.preposition)
+          .forContentType(header.value)
           .getOrElse(MediaType.application.`octet-stream`) // Unknown content type defaults to binary
     }.getOrElse(MediaType.text.plain) // Missing content type defaults to text
 
@@ -213,7 +213,7 @@ object FormField {
       disposition <- ZIO.fromOption(extract._1).orElseFail(FormDataMissingContentDisposition)
       name        <- ZIO.fromOption(extract._1.flatMap(_.fields.get("name"))).orElseFail(ContentDispositionMissingName)
       contentType      = extract._2
-        .flatMap(x => MediaType.forContentType(x.preposition))
+        .flatMap(x => MediaType.forContentType(x.value))
         .getOrElse(MediaType.text.plain)
       transferEncoding = extract._3
         .flatMap(x => ContentTransferEncoding.parse(x.preposition).toOption)
diff --git a/zio-http/src/main/scala/zio/http/MediaType.scala b/zio-http/src/main/scala/zio/http/MediaType.scala
index 48a54a8775..70390e5a36 100644
--- a/zio-http/src/main/scala/zio/http/MediaType.scala
+++ b/zio-http/src/main/scala/zio/http/MediaType.scala
@@ -42,7 +42,7 @@ object MediaType extends MediaTypes {
       val (contentType1, parameter) = contentType.splitAt(index)
       contentTypeMap
         .get(contentType1)
-        .map(_.copy(parameters = parseOptionalParameters(parameter.tail.split(";"))))
+        .map(_.copy(parameters = parseOptionalParameters(parameter.split(";"))))
     }
   }
 
@@ -76,6 +76,6 @@ object MediaType extends MediaTypes {
       case _                         => parameterMap
     }
 
-    loop(parameters.toIndexedSeq, Map.empty)
+    loop(parameters.toIndexedSeq, Map.empty).map { case (key, value) => key.trim -> value.trim }
   }
 }
diff --git a/zio-http/src/main/scala/zio/http/internal/FormAST.scala b/zio-http/src/main/scala/zio/http/internal/FormAST.scala
index d86cc51fd1..ac21d6ecfb 100644
--- a/zio-http/src/main/scala/zio/http/internal/FormAST.scala
+++ b/zio-http/src/main/scala/zio/http/internal/FormAST.scala
@@ -108,8 +108,11 @@ private[http] object FormAST {
     private def makeField(name: String, value: Option[String]): String =
       value.map(makeField(name, _)).getOrElse("")
 
-    def contentType(contentType: MediaType, charset: Option[Charset] = None): Header =
-      Header("Content-Type", s"${contentType.fullType}${makeField("charset", charset.map(_.name))}")
+    def contentType(contentType: MediaType): Header =
+      Header(
+        "Content-Type",
+        s"${contentType.fullType}${contentType.parameters.map { case (name, value) => s"; $name=$value" }.mkString("")}",
+      )
 
     def contentDisposition(name: String, filename: Option[String] = None): Header =
       Header("Content-Disposition", s"""form-data${makeField("name", name)}${makeField("filename", filename)}""")
diff --git a/zio-http/src/test/scala/zio/http/FormSpec.scala b/zio-http/src/test/scala/zio/http/FormSpec.scala
index d256f2210a..b66a884387 100644
--- a/zio-http/src/test/scala/zio/http/FormSpec.scala
+++ b/zio-http/src/test/scala/zio/http/FormSpec.scala
@@ -85,6 +85,29 @@ object FormSpec extends ZIOSpecDefault {
         form2 == form,
       )
     },
+    test("encoding with custom paramaters [charset]") {
+
+      val form = Form(
+        FormField.textField(
+          "csv-data",
+          "foo,bar,baz",
+          MediaType.text.csv.copy(parameters = Map("charset" -> "UTF-8")),
+        ),
+      )
+
+      val actualByteStream = form.multipartBytes(Boundary("(((AaB03x)))"))
+
+      def stringify(bytes: Chunk[Byte]): String =
+        new String(bytes.toArray, StandardCharsets.UTF_8)
+
+      for {
+        form4       <- Form.fromMultipartBytes(multipartFormBytes4)
+        actualBytes <- actualByteStream.runCollect
+      } yield assertTrue(
+        stringify(actualBytes) == stringify(multipartFormBytes4),
+        form4.formData.head.contentType == form.formData.head.contentType,
+      )
+    },
     test("decoding") {
       val boundary = Boundary("AaB03x")
 
diff --git a/zio-http/src/test/scala/zio/http/forms/Fixtures.scala b/zio-http/src/test/scala/zio/http/forms/Fixtures.scala
index 8b42d7d976..0c8de402ea 100644
--- a/zio-http/src/test/scala/zio/http/forms/Fixtures.scala
+++ b/zio-http/src/test/scala/zio/http/forms/Fixtures.scala
@@ -89,6 +89,16 @@ object Fixtures {
          |""".stripMargin.getBytes(),
     )
 
+  val multipartFormBytes4 =
+    Chunk.fromArray(
+      s"""|--(((AaB03x)))${CR}
+          |Content-Disposition: form-data; name="csv-data"${CR}
+          |Content-Type: text/csv; charset=UTF-8${CR}
+          |${CR}
+          |foo,bar,baz${CR}
+          |--(((AaB03x)))--${CRLF}""".stripMargin.getBytes(),
+    )
+
   private def simpleFormField: Gen[Any, (FormField, Schema[Any], Option[String], Boolean)] =
     for {
       name         <- Gen.option(Gen.string1(Gen.alphaNumericChar))