The proper cementation of a liner is an operation essential to the completion of an oilwell. A low fluid loss rate is required to prevent setting of the cement slurries before proper placement is achieved. Modified natural polymers are, at the present time, the most common fluid loss additives. However, temperature instability, retardation and high viscosity of the cement slurries are undesirable side effects of these additives. We have synthesized and tested a series of polymers and copolymers to identify potential fluid loss additives and to study the effect of various substituents on the effectiveness of the final material. Measurements of fluid loss, free water, rheology, thickening time and compressive strengths show that the developoment of good fluid loss control additives for cement depend upon careful control of copolymer composition and molecular weight.