Jonckheere (1954) proposed a test for ordered alternatives in a design withktreatments andblevels of another factor (blocks). In this paper tables are given for the null distribution of Jonckheere's statistic. Exact probabilities and critical values are given for α-levels near .2, .l, .05, .01 and .001, wherek= 2(1)6 andb= 2(1)5. Tables appear for designs in which there are an equal number of observations in treatments within a block, with cell sample sizes ranging from one to five.