The IMSL Routine MDSTI, found in most computer libraries, is supposed to give the quantiles of a t-distributed random variable for given significant level Q and degrees of freedom F. The routine does not give correct 't' values when F is in the range (1.2). In this paper, a code is produced, based on a relation between the 't' and 'F' distributions, which can effectively and efficiently overcome the error in MDSTI.