Techniques for re-using sequence number by multiple protocols in a protocol stack are described. In one design, at least one protocol data unit (PDU) from a first protocol may be received as at least one service data unit (SDU) at a second protocol, with each PDU being assigned a different sequence number by the first protocol. A sequence number for each SDU may be determined based on a sequence number for a corresponding PDU from the first protocol. A PDU may be formed by the second protocol based on the at least one SDU. A header may be generated for the PDU and may include (i) the sequence number and possibly a segment offset for the first SDU and (ii) a header block for each remaining SDU, which may include a segment length, a sequence number offset, and a segment offset for that SDU.