The present invention provides process for preparation of cysteamine bitartrate comprising reacting cysteamine or its salt with tartaric acid. The present invention further provides crystalline form L1 of cysteamine bitartrate having characteristic diffraction peaks at 10.36, 14.54, 17.23, 18.03, 19.24, 20.76, 21.20, 22.02, 23.37, 23.64, 27.71, 28.28, 29.26, 31.33, 32.84, 33.83, 35.51, 36.74±0.2 degree two theta in an X-ray diffraction pattern and process for preparation thereof. The present invention provides crystalline form L2 of cysteamine bitartrate having characteristic diffraction peaks at 7.4, 10.3, 11.0, 11.4, 14.4, 14.9, 18.6, 19.4, 20.1, 20.8, 21.9, 22.3, 22.5, 23.5±0.2 degree two theta in an X-ray diffraction pattern and process for preparation thereof.
