The primary focus of pain research in intellectually disabled individuals is still on pain assessment. Several observational pain assessment scales are available, each with its own characteristics, its own target group and its own validated use. Observational studies report differences in the treatment of intra-and postoperative pain of intellectually disabled children and almost all children with intellectual disability have comorbidities that need to be addressed. The scope of research has started to broaden. In this review we aim to answer the question: Can we integrate validated ways of pain assessment and postoperative pain treatment in intellectually disabled children to develop specific analgesic algorithms? Regrettably there is little knowledge on possible interaction effects and other relevant pharmacological issues. Possible genotype-phenotype associations related to pain in children with Down syndrome have several promises as six possible candidate genes are located on chromosome 21. In conclusion, the pain assessment tools for intellectually disabled children are there. We should now focus on tailoring the pain treatment. To this aim we need to perform pharmacokinetic and pharmacodynamic studies of analgesics and obtain information about the genotype-phenotype relationships for pain. This can lead to the development of specific analgesic algorithms. (C) 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:248-257.