Abstract In this paper, we consider a hybrid flowshop scheduling problem with mixed blocking constraints. This production system is prevalent in industrial environments where number of machines at each stage may be more than one and buffer space capacities between successive stages may be unlimited, limited or null. In flowshop scheduling literature, many studies and researches were realized about classical hybrid flowshop problem and also about some problems with only one blocking constraint between all stages. But only few works have dealt with different blocking constraints in a same flowshop scheduling problem. This paper deals with makespan minimization in flowshop scheduling problems where mixed blocking constraints are considered. After a problem description, an integer linear programming model is presented and a lower bound is proposed and evaluated.