Effective scheduling of operations in batch plants has a great potential for high economic returns, in which the formulation and optimal solution algorithm are the main issues of study. Petri-nets have proven to be a promising technique to solve many difficult problems associated with the modeling, formal analysis, design and coordination control of discrete event systems. One of the major advantages of using a Petri-net model is that the same model can be used for the analysis of behavioral properties and performance evaluation, as well as for the systematic construction of discrete event simulators and controllers. This paper aims to present a Petri-net based approach for the scheduling of operations in batch plants. Firstly, the short-term scheduling of batch plants is formulated using timed Petri-net. Secondly, the heuristic search algorithm for scheduling of batch plants is given, which is based on generating and checking the markings in the reachability tree of the Petri-net model. Finally, the novel formulation and algorithm are tested using two simulation case studies, and compared against traditional methods. (C). 2004 Elsevier Ltd. All rights reserved.