Due to hot weather in Egypt, especially in the summer, concrete pouring needs to be under certain circumstances, where concrete need addition of some additives to increase workability and delay the initial setting time. In this paper, we study the influence of superplasticizer dose on performance of concrete.Ordinary Portland Cement (OPC) and sulfonated naphthalene formaldehyde (SNF) condensate is used. Concrete mixes with SP dosages of 700, 1000, 1500, 2000 and 2500 ml/100kg of cement were prepared. The w/c ratio of the control mix is 0.54. The first aim of the present work is to further examine the influence of SP addition on the properties of concrete were investigated at a constant water to cement (w/c) ratio is 0.54% and variable of w/c ratio. The second aim to find optimum dosage of superplasticiser in concrete to improve the properties of concrete. The results revealed that:- The workability (slump value) and setting time (initial and finial) of concrete increased with increasing % of SP, the highest and lowest values of slump and setting time were obtained with the addition of 0.7% and 2.5% superplasticizer respectively. The compressive strength reaches its maximum value at 2% SP, this at constant water to cement (w/c) ratio 0.54%.