Concrete's compressive strength is perhaps the most relevant material factor to take into account while designing structural elements. However, using this value has become challenging because control specimen sizes vary from nation to nation. Many studies were conducted in past to analyse the specimen size and shape effects on the compressive strength of concrete. The previous investigations were conducted on different sized cylinders and cubes. The mechanical strength values of the specimens were observed to be decreased than the bigger specimen. In the present study efforts are made to study the effect on cube compressive strength for 150mm and 300mmspecimen size for a uniform concrete mix.