diff --git a/src/authenticator.rs b/src/authenticator.rs
new file mode 100644
index 0000000..16004a1
--- /dev/null
+++ b/src/authenticator.rs
@@ -0,0 +1,3 @@
+pub trait Authenticator {
+    fn process(&self, String) -> String;
+}
diff --git a/src/client.rs b/src/client.rs
index 6eaa98b..0f5e98d 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -3,7 +3,8 @@ use openssl::ssl::{SslContext, SslStream};
 use std::io::{self, Read, Write};
 
 use super::mailbox::Mailbox;
-use super::parse::{parse_response_ok, parse_capability, parse_select_or_examine, parse_response};
+use super::authenticator::Authenticator;
+use super::parse::{parse_response_ok, parse_capability, parse_select_or_examine, parse_response, parse_authenticate_response};
 use super::error::{Error, Result};
 
 static TAG_PREFIX: &'static str = "a";
@@ -59,6 +60,32 @@ impl<T: Read+Write> Client<T> {
 		}
 	}
 
+	pub fn authenticate<A: Authenticator>(&mut self, auth_type: &str, authenticator: A) -> Result<()> {
+		match self.run_command(&format!("AUTHENTICATE {}\r\n", auth_type).to_string()) {
+			Ok(lines) => {
+				// TODO test this for the many authentication use cases
+				let data = match parse_authenticate_response(lines) {
+					Ok(d) => d,
+					Err(e) => return Err(e)
+				};
+				let auth_response = authenticator.process(data);
+				match self.stream.write_all(auth_response.into_bytes().as_slice()) {
+					Err(e) => return Err(Error::Io(e)),
+					_ => {}
+				};
+				match self.stream.write(vec![0x0d, 0x0a].as_slice()) {
+					Err(e) => return Err(Error::Io(e)),
+					_ => {}
+				};
+				match self.read_response() {
+					Ok(_) => Ok(()),
+					Err(e) => return Err(e)
+				}
+			},
+			Err(e) => Err(e)
+		}
+	}
+
 	/// Log in to the IMAP server.
 	pub fn login(&mut self, username: & str, password: & str) -> Result<()> {
 		self.run_command_and_check_ok(&format!("LOGIN {} {}", username, password).to_string())
diff --git a/src/error.rs b/src/error.rs
index 4d2cd89..40a75a4 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -69,7 +69,9 @@ pub enum ParseError {
     // Indicates an error parsing the status response. Such as OK, NO, and BAD.
     StatusResponse(Vec<String>),
     // Error parsing the cabability response.
-    Capability(Vec<String>)
+    Capability(Vec<String>),
+    // Authentication errors.
+    Authentication(Vec<String>)
 }
 
 impl fmt::Display for ParseError {
@@ -84,7 +86,8 @@ impl StdError for ParseError {
     fn description(&self) -> &str {
         match *self {
             ParseError::StatusResponse(_) => "Unable to parse status response",
-            ParseError::Capability(_) => "Unable to parse capability response"
+            ParseError::Capability(_) => "Unable to parse capability response",
+            ParseError::Authentication(_) => "Unable to parse authentication response"
         }
     }
 
diff --git a/src/lib.rs b/src/lib.rs
index affa530..18ef667 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,6 +6,7 @@
 extern crate openssl;
 extern crate regex;
 
+pub mod authenticator;
 pub mod client;
 pub mod error;
 pub mod mailbox;
diff --git a/src/parse.rs b/src/parse.rs
index 0fa7651..38e2d34 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -3,6 +3,21 @@ use regex::Regex;
 use super::mailbox::Mailbox;
 use super::error::{Error, ParseError, Result};
 
+pub fn parse_authenticate_response(lines: Vec<String>) -> Result<String> {
+    let authenticate_regex = Regex::new("^+ (.*)\r\n").unwrap();
+    let last_line = match lines.last() {
+        Some(l) => l,
+        None => return Err(Error::Parse(ParseError::Authentication(lines.clone())))
+    };
+
+    for cap in authenticate_regex.captures_iter(last_line) {
+        let data = cap.at(1).unwrap_or("");
+        return Ok(String::from(data));
+    }
+
+    Err(Error::Parse(ParseError::Authentication(lines.clone())))
+}
+
 pub fn parse_capability(lines: Vec<String>) -> Result<Vec<String>> {
     let capability_regex = Regex::new(r"^\* CAPABILITY (.*)\r\n").unwrap();