We consider IPM as a combination of durable, environmentally, toxicologically and economically justifiable farming practices which prevent pest damage primarily through the use of natural factors limiting pest population growth and disease development, and which resort only if needed to other, preferably non-chemical, measures. IPM is not simply a combination of various control methods. We give an overview of IPM measures used in greenhouses and refer to specific chapters in this book for examples. In IPM, each practical situation dictates a number of special aspects for consideration, and IPM methods need continuous adaptation, making IPM knowledge intensive and interactive. Successful IPM programmes for greenhouse crops have a number of characteristics in common: (a) their use was promoted only after a complete IPM programme had been developed, (b) intensive support by the extension service was essential during initial implementation, (c) the costs of crop protection with IPM should not be higher than those of a chemical control programme, and (d) non-chemical management methods, such as biocontrol agents and resistant plant material, should be as easily available, as reliable, and as constant in quality, as chemical agents. IPM research and implementation in greenhouses during the past 50 years has taught us the lesson that the development of an IPM programme needs to be discussed in a very early stage with all stakeholders, including growers, pest management specialists, extension services and researchers. Such a meeting often results in a pragmatic design of a draft, very pragmatic IPM programme, which is continuously adapted during later meetings, based on growers’ experience and new research results.