Objective-A Medline electronic search showed a paucity of reports on calcium pyrophosphate dihydrate crystal deposition disease (CPPD-CDD) from the Gulf region. To date only a single case report has been published from this region. Therefore, this study aimed, firstly, at finding out the prevalence of chondrocalcinosis in adult Arabs in Kuwait presenting with knee arthritis and, secondly, at carrying out an observational study of CPPD-CDD among Arabs in Kuwait. Methods-For the study of the prevalence of chondrocalcinosis 100 consecutive adult patients presenting with knee arthritis were radiologically examined. For the observational study the clinical, laboratory, and radiological findings were analysed in patients with CPPD-CDD seen over a period of five years. Results-This study showed the presence of chondrocalcinosis in two (2%) of the 100 adult Kuwaiti and other Middle-Eastern Arab patients (70 men, 30 women, median age 50 (range 45-80)) who presented to the rheumatology clinic for the evaluation of knee pain. When the younger age of the group (only three patients aged >70) is taken into account the figure was comparable with that reported from Western countries. Over a period of five years a total of 2726 new patients were evaluated at the rheumatology clinic of this institution. A diagnosis of crystal arthritis was made in 85 patients (3%). Fourteen of these 85 (that is, 16.5%, but 0.5% of the total cases) were diagnosed with definite (eight patients) or probable (six patients) CPPD-CDD. DiVerent clinical presentations, including that of acute monarthritis (that is, pseudogout), premature generalised osteoarthritis, and polyarticular rheumatoid-like presentations, were seen in diVerent patients. Overlap with true gout, with the additional presence of monosodium urate crystals in the joint aspirate, was seen in two patients.