The expression of the Epstein‐Barr virus LMP1 oncogene is regulated by viral and non‐viral factors in a tissue dependent fashion. The virus encoded transcription factor EBNA2 induces its expression in human B‐cells. However, this induction also requires the contribution of cellular and/or other viral factors. In nasopharyngeal carcinoma cells and in cells from Hodgkin's lymphoma, LMP1 gene transcription is independent of viral products. Here we show that the effect of a factor binding to a cAMP responsive‐like element (CRE) in the LMP1 gene transcription regulatory sequence (LRS) is essential for efficient promoter activity in the DG75 B‐cell line and that elevation of cAMP levels in the cells induces LRS‐derived CAT activity in a CRE dependent fashion. Incubation of two EBV‐immortalized B‐cell lines expressing endogenous EBNA2A with 8‐Br cAMP increased the levels of the latency associated 66 kDa LMP1 within 2 h. Interestingly, LMP1 expression in DG75 cells conferred resistance to the inhibitory effect of 8‐Br cAMP on cell proliferation. The protein phosphatase 1 and 2A (PP1 and PP2A, respectively) inhibitor okadaic acid also stimulated LRS‐CAT activity in DG75 cells. EBNA2A from an EBV‐immortalized B‐cell line co‐immunopurified with a PP1‐like protein. An EBNA2A fragment spanning residues 324‐436 fused to the GST protein specifically rescued a PP1/PP2A‐like component from DG75 cell extracts. This GST‐EBNA2A fusion product inhibited a PP1‐like activity in nuclear extracts from these cells.