Amphetamine type stimulants (ATS) are commonly used in Vietnam and its use is rapidly increasing. This study used data of mixed method cross-sectional study on ATS among FSWs in Hanoi. Objectives: To describe knowledge, attitudes, and practices towards ATS among FSWs in Hanoi. Results: FSWs are more familiar with estacy and crystal Methamphetamine (da) than meth-amphetamine tablet. Increased sexual desire and hallucinations are the most common effects reported by FSWs. Some FSWs considered the use of ATS to showcase their leve) and fashion, such that over 30 percent FSWs have perception that crystal methamphetamine could be used once time to have "experience". The ATS usage rate is 64,5 percent, with crystal methamphetamine being the most popular drug used among FSWs (50,6 percent). Conclusion: FSWs lack specific knowledge about ATS, with some having a wrong attidute towards ATS usage. The rate of ATS usage among FSWs in this study is relatively high, especially the use of crystal methamphetamin. Recommendation: interventions are needed to prevent ATS use among FSWs and should focus on crystal methamphetamine prevention.