Code division multiple access (CDMA) is a widelyused multiple-access scheme in conventional communication systems. In this paper, we consider code division multiple access in molecular communication: since molecular communication has a non-negativity constraint, we consider a nonnegative variant of CDMA that was developed for optical communication. Our results include an information transmission scheme, and an algorithm to decode molecular information signals. We also analyze the system based on realistic propagation models obtained from experimental apparatus. Finally, we demonstrate reliable communication with multiple access by using this scheme.