A semi-cylinderical greenhouse is simple in construction, requires less material and can withstand high wind pressure. The transmission of solar radiation through the curved surface is dependent on angle of incidence of solar radiation on the cover. A calculation procedure has been developed for the transmission of obliquely incident beam radiation through a semi-cylindrical greenhouse. An analysis has also been presented for total solar radiation entering the greenhouse on a typical day for N-S and E-W orientations of the greenhouse for semi humid climate of Udaipur (27°42' N, 75°33' E) Rajasthan, India. It is found that E-W oriented greenhouse receives more solar radiation as compared to N-S oriented greenhouse for typical winter month of December by about 7.67%, whereas N-S oriented greenhouse receive less radiation energy by about 2.56% as compared to E-W oriented greenhouse for the typical summer month of May. Key words: Angle of incidence, greenhouse, semi-cylindrical surface, solar radiation, transmittance.