This article describes the development of a novel sequential sampling method for the surveillance of transmitted HIV drug resistance by cross-sectional survey. Two commonly used sequential sampling methods are described and their applicability to the problem of classifying the prevalence of transmitted HIV drug resistance investigated. Both methods are rejected due to insufficient savings in sample size and operational complexity. A novel method is proposed and this is tested using computer-based simulation. This method provides useful sample size savings and operational simplicity and could provide the basis for a rapid and reliable survey method for classifying the prevalence of transmitted HIV drug resistance in circumstances where monitoring HIV drug resistance is an important issue, but resources do not allow fullscale surveillance to be established. The method is currently being used in several such settings.