The increased emphasis on the production of low-volume, high-value-added products has resulted in a renewed interest in multipurpose batch plants, which tend to be the most economical facilities for the production of small amounts of many different products. In such plants, the competition between the different products for the shared production resources gives rise to complex production scheduling problems. Amongst other factors, the profitability of a plant also depends on its availability which directly depends on the maintenance work carried out. In multipurpose plants, the integrated planning of production and maintenance so that these problems are solved simultaneously should result in increased profitability compared to the case where they are solved in isolation. This may be due, for example, to the ability to exploit equipment idle time or redundancy to perform preventive maintenance while having a minimal effect on production. This paper describes a mathematical model for simultaneously scheduling production and maintenance activities within a multipurpose plant, taking account of both production resources (e.g., equipment items) and maintenance resources (eg., crews).