In this paper we propose a multiuser receiver using multistage detection and interference cancellation for direct-sequence code-division multiple-access (DS/CDMA) systems with parity bit selected spreading sequences in synchronous channels. In a CDMA system with parity bit selected spreading sequences (CDMA/PB), the spreading code used by each user depends on the transmitted data bits and it is selected from a set of mutually orthogonal spreading waveforms allocated to each user. Multistage parallel interference cancellation (PIC) detector is used to estimate and subtract out all multiple-access interference (MAI) for each user in parallel. The performance of the proposed system is compared with the conventional uncoded CDMA systems.