目的：本研究之目的爲探討注射藥癮者的保險套使用行爲及分析影響使用保險套之相關因素。方法：研究對象爲2009年2月在台中市某醫學中心接受美沙冬治療門診的個案，經解釋研究目的後同意參加者共192位（男性142位，女性50位），研究工具採半結構式問卷，內容包括個人基本資料、性經驗與保險套使用情形，由受訓訪員與受訪者一對一填答，統計方法則以卡方檢定、獨立樣本t檢定及McNemar進行分析比較。結果：192位受訪者中有99%的人有過性經驗，第一次性行爲平均年齡爲17.8歲；受訪者在訪談前一個月與固定性伴侶每次都使用保險套比率26.4%；受訪者發生性行爲時未能每次都使用保險套的原因主要爲手邊沒有、沒必要使用及不方便取得；受訪者中約有26.4%其性伴侶也同爲注射藥癮者；較安全性行爲與不安全性行爲兩組在HIV篩檢結果、保險套的不舒服感與保險套使用及購買的麻煩達到統計顯著差異；受訪者在美沙冬治療後傾向只有一個性伴侶及較安全性行爲。結論：本研究結果發現注射藥癮者性交時未能採行較安全性行爲的原因與影響因素，可做爲國內推展藥癮愛滋防治衛生教育參考，並得以發展以藥癮者爲主的行爲改變介入教育課程，引導注射藥癮者安全性行爲的產生。

The purpose of this study was to explore the condom use behavior and the related factors among injection drug users (IDU). The participants were the outpatients who received Methadone substitution treatment at a medical center in Taichung City in Feb. 2009. The trained interviewer conducted interviews with 192 consenting participants (male 142, female 50). The semi-structured questionnaire included demographic information, sexual experience, and condom use behavior. Data were collected and analyzed with SPSS 12.0. The results indicated that 99% of the participants (N=192) had sexual experience, with their first sexual experience occurring at the mean age of 17.8. Only 26.4% of the participants were using condoms with their primary partners each time during one month prior to the interview. The reasons for not having used condoms were: unavailability, no necessity, and inconvenience. Approximately 26.4% of the participants had drug-using sex partners. There was a significant difference between the safer sex group and unsafe sex group in terms of HIV screen test result, discomfort of using condoms and inconvenience of using and purchasing condoms. The findings could be useful for designing the AIDS intervention programs in health education as well as developing the behavior change programs on safer sex for injection drug users.