Computer-generated random number is a kind of pseudo-random number. So far various tests of random numbers have been performed. However, comparisons of random numbers generated by different programming languages have not been made. Generally, random numbers are often used when simulation is conducted using a computer. Therefore it is important to compare the variation of random numbers resulting from different programming languages used. In the present study, the comparison among three types of programming languages, namely, the C, Pascal and the Basic, is made by calculating number π using Monte Carlo method.