In this study Methylmethacrylate and Ethylenediammine have been used as additive in high strength Portland cement and its impact on the cementing properties (water of consistency, setting time and hydration behavior i.e., combined water at different curing times; 3, 7 and 28 days) has been studied. Different doses (1, 2, 3, 4 and 5 %) of methylmethacrylate (C5H9O2) and ethylenediammine (C2N2H8) were added to high strength Portland. Results indicated that methylmethacrylate acts as a setting retarder with increasing water of consistency, it has a negative effect on  hydration properties, however when present in limited content (not more than 2 %) its negative effect is relatively slight. On the other hand, ethylenediammine acts as a water reducing and setting accelerator agent, its addition up to 3 % results in a remarkable improvement in the above-mentioned properties