This retrospective descriptive study aimed to evaluate and compare the quality analysis of generic drugs available in Songklanagarind Hospital drugs list. One thousand six hundred and sixty eight samples of the quality analysis of the generic drugs data were collected during the period of October 1, 1990 to September 30, 2010 from the electronic database called “Hospital Information System”. Data were analysed using descriptive statistics of frequency, percentage and average, and using chi-square test for independence testing between the result of the quality analysis of drug and dosage form, pharmacological group, standard testing, type of sampling drug and the source of drug manufacturing. The results revealed that 1,534 samples (92.0%) of the analyzed products met the Pharmacopoeia standards, while 134 samples (8.0%) were substandard with respect to dissolution. The quality of the generic drugs were statistically significantly associated with the source of drug manufacturing. (p<0.001)