Abstract Let X1, X2 and X3 be independent random variables, X1 and X2 having a confluent hypergeometric function kind 1 distribution with probability density function proportional to , i = 1, 2 , and X3 having a standard gamma distribution with shape parameter v3. Define W1 = X1/(X1 + X3) and W2 = X2/(X2 + X3). In this article we derive the joint probability density function of W1 and W2 and study its properties.