TWO different superplasticizers particularly Cyclohexanone formaldehyde sulfanilate (CFS) and Cyclohexanone glyoxylic sulfanilate (CGS) were prepared; also, their effect on mechanical and physico-chemical properties of oil well cement was assessed. The chemical structures were affirmed by FTIR technique. The designed chemical compounds were predestined as superplasticizers for cement pastes. The pastes made by superplasticizers (CFS or CGS) addition to cement by the ratios of 0, 0.25, 0.50, 0.75, and l.00 as mass % of cement. The consistence water, setting time, chemically combined water content (Wn), the hydration rate and compressive strength of the admixed hardened pastes were predestined at various time periods. The phase composition was intended by DSC and XRD techniques. The results revealed that as the admixture dose rate increases the demand cement paste water of consistency decreases. Also, as the admixture addition rate increases the chemically combined water content decreases, so the rate of hydration decreases; meanwhile compressive strength magnitudes increase in accounts for the low water/cement (initial porosity) of the sample.