This paper deals with the study of split plot design in balanced incomplete blocks in order to increase the usage of such designs in the agricultural research. The mathematical model adopted was the one traditionally used in the complete design. The presence of constant correlation between two subplots of the same plot and the subplots of distinct plots were considered as well. The estimates of the main treatments adjusted by block effects were analogous to those found in the literature of the balanced incomplete block design, while the other estimates were analogous to the correspondent ones in the split plot randomized block design.