OBJECTIVE To screen the level of novel drug resistance mutations in subtype B' in China. METHODS 451 pol sequences collected from the previous study, which including 354 AIDS patients who had received antiretroviral treatment (ART) and 97 the untreated patients. Entire protease gene (codons 1 - 99) and full-length reverse transcriptase gene (codons 1 - 560) were included. Variation of mutations between the treated and the untreated patients with consensus/ancestral sequences were compared and the mutations with higher frequencies in the treated patients than in the untreated patients were screened before submitting the mutations to the Stanford HIV Drug Resistance Database (SHDB) (http: //hivdb.stanford.edu/). Relation between the mutations and resistance preliminarily was then analyzed, according to the information including SHDB. RESULTS Frequencies of 7 mutations at 6 positions, D123E, V292I, K366R, T369A, T369V, A371V and I375V, 2 at DNA polymerase domain and 5 at connection domain of reverse transcriptase (RT) were higher in the treated patients than in the untreated patients. The information of 7 mutations including the SHDB showed that 7 mutations were major variants at corresponding positions, and theirs frequencies were higher in the treated patients using some drugs, than in the untreated patients. CONCLUSIONS 7 mutations being screened from the China subtype B were possibly associated with the resistance, which called for the construction of mutated viruses by site-directed mutagenesis to identify their effects on the susceptivity of different drugs.