diff --git a/random-fu.cabal b/random-fu.cabal
--- a/random-fu.cabal
+++ b/random-fu.cabal
@@ -1,5 +1,5 @@
 name:                   random-fu
-version:                0.2.4.0
+version:                0.2.5.0
 stability:              provisional
 
 cabal-version:          >= 1.6
@@ -76,6 +76,7 @@
                         Data.Random.Distribution.Pareto
                         Data.Random.Distribution.Poisson
                         Data.Random.Distribution.Rayleigh
+                        Data.Random.Distribution.T
                         Data.Random.Distribution.Triangular
                         Data.Random.Distribution.Uniform
                         Data.Random.Distribution.Weibull
@@ -99,7 +100,7 @@
   else
     build-depends:      mtl == 1.*
   
-  build-depends:        gamma,
+  build-depends:        math-functions,
                         monad-loops >= 0.3.0.1,
                         random-shuffle,
                         random-source == 0.3.*,
diff --git a/src/Data/Random/Distribution/ChiSquare.hs b/src/Data/Random/Distribution/ChiSquare.hs
--- a/src/Data/Random/Distribution/ChiSquare.hs
+++ b/src/Data/Random/Distribution/ChiSquare.hs
@@ -8,7 +8,7 @@
 import Data.Random.Distribution
 import Data.Random.Distribution.Gamma
 
-import Math.Gamma (p)
+import Numeric.SpecFunctions
 
 chiSquare :: Distribution ChiSquare t => Integer -> RVar t
 chiSquare = rvar . ChiSquare
@@ -25,4 +25,4 @@
         | otherwise = fail "chi-square distribution: degrees of freedom must be positive"
 
 instance (Real t, Distribution ChiSquare t) => CDF ChiSquare t where
-    cdf (ChiSquare n) x = p (0.5 * fromInteger n) (0.5 * realToFrac x)
+    cdf (ChiSquare n) x = incompleteGamma (0.5 * fromInteger n) (0.5 * realToFrac x)
diff --git a/src/Data/Random/Distribution/Gamma.hs b/src/Data/Random/Distribution/Gamma.hs
--- a/src/Data/Random/Distribution/Gamma.hs
+++ b/src/Data/Random/Distribution/Gamma.hs
@@ -21,7 +21,7 @@
 
 import Data.Ratio
 
-import Math.Gamma (p)
+import Numeric.SpecFunctions
 
 -- |derived from  Marsaglia & Tang, "A Simple Method for generating gamma
 -- variables", ACM Transactions on Mathematical Software, Vol 26, No 3 (2000), p363-372.
@@ -80,11 +80,11 @@
     rvarT (Gamma a b) = mtGamma a b
 
 instance (Real a, Distribution Gamma a) => CDF Gamma a where
-    cdf (Gamma a b) x = p (realToFrac a) (realToFrac x / realToFrac b)
+    cdf (Gamma a b) x = incompleteGamma (realToFrac a) (realToFrac x / realToFrac b)
 
 instance (Integral a, Floating b, Ord b, Distribution Normal b, Distribution StdUniform b) => Distribution (Erlang a) b where
     rvarT (Erlang a) = mtGamma (fromIntegral a) 1
 
 instance (Integral a, Real b, Distribution (Erlang a) b) => CDF (Erlang a) b where
-    cdf (Erlang a) x = p (fromIntegral a) (realToFrac x)
+    cdf (Erlang a) x = incompleteGamma (fromIntegral a) (realToFrac x)
 
diff --git a/src/Data/Random/Distribution/T.hs b/src/Data/Random/Distribution/T.hs
new file mode 100644
--- /dev/null
+++ b/src/Data/Random/Distribution/T.hs
@@ -0,0 +1,46 @@
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE FlexibleInstances     #-}
+{-# LANGUAGE FlexibleContexts      #-}
+{-# LANGUAGE UndecidableInstances  #-}
+
+{-# OPTIONS_GHC -Wall                      #-}
+{-# OPTIONS_GHC -fno-warn-name-shadowing   #-}
+{-# OPTIONS_GHC -fno-warn-type-defaults    #-}
+{-# OPTIONS_GHC -fno-warn-unused-do-bind   #-}
+{-# OPTIONS_GHC -fno-warn-missing-methods  #-}
+{-# OPTIONS_GHC -fno-warn-orphans          #-}
+
+module Data.Random.Distribution.T where
+
+import Data.RVar
+import Data.Random.Distribution
+import Data.Random.Distribution.ChiSquare
+import Data.Random.Distribution.Normal
+
+import Numeric.SpecFunctions
+
+t :: Distribution T a => Integer -> RVar a
+t = rvar . T
+
+tT :: Distribution T a => Integer -> RVarT m a
+tT = rvarT . T
+
+newtype T a = T Integer
+    deriving (Eq, Ord, Show)
+
+instance (Floating a, Distribution Normal a, Distribution ChiSquare a) => Distribution T a where
+    rvarT (T n)
+        | n > 0     = do
+            x <- stdNormalT
+            y <- chiSquareT n
+            return (x * sqrt (fromInteger n / y))
+        | otherwise = fail "Student's t-distribution: degrees of freedom must be positive"
+
+instance (Real a, Distribution T a) => CDF T a where
+    cdf (T n) t = incompleteBeta v2 v2 x
+        where
+            v = fromIntegral n
+            v2 = 0.5 * v
+            tD = realToFrac t
+            u = sqrt (tD*tD + v)
+            x = (tD + u) / (u + u)
diff --git a/src/Data/Random/Distribution/Uniform.hs b/src/Data/Random/Distribution/Uniform.hs
--- a/src/Data/Random/Distribution/Uniform.hs
+++ b/src/Data/Random/Distribution/Uniform.hs
@@ -30,6 +30,7 @@
     , floatStdUniform
     , doubleStdUniform
     
+    , boundedStdUniformCDF
     , realStdUniformCDF
     , realUniformCDF
     ) where