Although the issue of substandard and falsified medicines is quite well known, most research has focused on medicines used to treat communicable diseases, and relatively little research has been carried out on the quality of medicines for noncommunicable diseases (NCDs). This study was designed to assess the quality of seven widely used medicines for NCDs in Cambodia during 2011-2013. Medicines were collected from private community drug outlets in Phnom Penh (urban area), by stratified random sampling and in Battambang, Kandal, Kampong Speu, and Takeo (rural areas) by convenience sampling. Samples were subsequently analyzed by visual inspection, authenticity investigation, and pharmacopoeial analysis by high-performance liquid chromatography. Various discrepancies were observed in visual inspection of packages and medicines. Of 372 tablet/capsule samples from 64 manufacturers in 16 countries, the manufacturers confirmed 107 (28.8%) as authentic; the authenticity of other samples could not be verified. Three hundred sixty-four (97.8%) samples were registered in Cambodia. Among all samples, 23.4% (95% CI 19.2-28.0) were noncompliant in one or more of the quality tests: 12.9% (95% CI 9.7-16.7) contained an amount of active pharmaceutical ingredient outside the permitted range, including some showing extreme deviations, 14% (95% CI 10.6-17.9) failed because of content variation, and 10.8% (95% CI 7.8-14.4) failed to meet pharmacopoeial reference ranges in dissolution tests. Pharmaceutical quality appeared to be unrelated to storage conditions. Although no sample was obviously falsified, there is a high prevalence of substandard medicines for NCDs in Cambodia, indicating the need for focused regulatory action, including collaborative initiatives with manufacturers.