Two series of new tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines namely 2,3-disubstituted derivatives 3a-z and 2,4-disubstituted ones 6a-c were prepared and tested for their antitumor and antibacterial activities. The structures of the prepared compounds were confirmed by spectral and elemental analyses. Compound 3z exhibited the highest antitumor activity against breast MCF-7 with IC50 = 0.19 μM compared to Doxorubicin (IC50 = 5.46 μM), while 3r was the most active one against liver HEPG-2 cancer cell line with IC50 = 1.29 μM as regard to Doxorubicin (IC50 = 7.36 μM). Concerning the antibacterial activity, compounds 3m and 3z exerted remarkable activity against the tested bacterial species compared to Ampicillin, whereas compound 6c showed good activity against only Gram positive species.