R package BuyseTest. Implementation of the Generalized Pairwise Comparisons. This test enables to compare two groups of observations in randomized trials(e.g treated vs. control patients) on several prioritized outcomes. Pairwise comparisons require consideration of all possible pairs of individuals, one taken from the treatment group and the other taken from the control group. The outcomes of the two individuals forming a pair are compared. Thresholds of minimal clinically significant differences can be defined. It is possible to analyse simultaneously several outcomes by prioritizing the variables that capture them. The highest priority is assigned to the variable considered the most clinically relevant. A natural way of handling uninformative or neutral pairs is to consider the outcomes in descending order of priority: whenever a pair is uninformative or neutral for an outcome of higher priority, the outcomes of lower priority are examined In the case of time-to-event endpoint, four methods to handle censored observations are available in this package (Gehan, Peto, Efron, and Peron).