Objective: The purpose of this study was to compare the success rates of glass-ionomer cement restorations placed with the atraumatic restorative treatment approach and conventional cavity preparation methods. Method and materials: Two encapsulated, high-strength, esthetic conventional glass-ionomer cements were placed in 82 Class I and 53 Class II atraumatic restorative treatment and conventional cavity preparations, and an encapsulated amalgam alloy was placed in 32 Class I conventional preparations, in vital primary molars of 60 Chinese children aged 7 to 9 years. Results: The atraumatic restorative treatment preparations, made with hand instruments only, took approximately 50% longer to complete than did the preparations completed with conventional rotary instrumentation. After 1 year, there were no amalgam failures. For the glass-ionomer cement restorations, when the atraumatic restorative treatment method was used, significantly better survival rates were found for Class I (92.9%) than for Class II (64.7%) cavity preparations. There was also a strong trend for relatively better survival rates for the conventional cavity preparation method (86.7%) than for the atraumatic restorative treatment (64.7%) method for Class II cavity preparations. However, both the atraumatic restorative treatment and conventional methods appeared equally effective for Class I preparations. Conclusion: In a clinic setting, the use of atraumatic restorative treatment hand instruments for cavity preparation is more time consuming, and the method may also provide less mechanical retention and/or bulk of glass-ionomer cement for some Class II preparations in primary molars than does the use of conventional rotary instruments.