The impact of medical documentaries on attendance to immunization sessions is not documented in developing countries. The impact of a video and TV medical documentary on women's vaccination during a catch-up tetanus collective immunization was studied in Cambodia (2002-2004). A medical video documentary produced locally was publicly shown in 10 villages chosen at random among 63 villages to be covered by collective tetanus immunization. In each village where the video was shown, 33 women, older than age 11, were selected at random and questioned about their tetanus vaccination records, to assess if they attended the video and to evaluate their knowledge about tetanus. A second interview was conducted after the first collective vaccination to check their attendance and to record reasons for non-attendance. The same interview was conducted 10 months later, after the documentary was shown on a local TV channel and a second collective tetanus vaccination conducted. Data were collected from 323 (98%) women. Seventy-eight (24%) women saw the video documentary and only eight (2.4%) saw it on TV. Compared to farmers, shopkeepers saw significantly less the documentary (χ² of Yates: 5.77,P = 0.016; 95% CI: 0.10 < RR = 0.29 < 0.88) and no home keeper or civil servant attended it. Women of childbearing age with no school education were significantly more attracted by the video documentary (χ² of Yates: 5.99,P = 0.01; 95% CI: 1.10 < RR = 1.57 < 2.22) than other childbearing-aged women, although their final immunization coverage was not better. The documentary did not increase the knowledge that contamination for tetanus may come from earth and tools, but not from air and water, and that all ages are at-risk for tetanus, but it increased significantly the knowledge that vaccination can prevent the disease (χ² of Yates: 13.98;P = 0.0001; 95% CI: 1.28 < RR = 1.57 < 1.93). Women who saw the video documentary attended the first collective session more often than those who did not (χ² of Yates: 11.00; P = 0.0006; 95% CI: 1.23 < RR = 1.51 < 1.84)in spite of their better vaccination status before the immunization, and this was mostly significant for farmers and women more than 45 years of age. Women who saw the documentary either on video or on TV also attended more the second collective session, but not significantly (χ² of Yates: 1.23;P = 0.266; 95% CI: 0.91 < RR = 1.23 < 1.66). Forty-nine percent of women had not attended school and the video documentary was re-run twice after the first performance. Women older than 45 years (55%) completely escaped immunization significantly more often than women of childbearing age (35%) (χ² of Yates: 17.26;P = 0.00003, 95% CI: 1.53 < RR = 2.13 < 2.97), who did it more often than schoolgirls (2%) (χ² of Yates: 9.69;P = 0.002; 95% CI: 0.01 < RR = 0.09 < 0.65). The main reasons for not being vaccinated during catch-up collective tetanus vaccinations were a too short interval between doses according to the WHO schedule (25%), agricultural task (18%), leisure travel (8%), fear of injections (7%), and being completely vaccinated according to the WHO schedule (7%). Only 2% of women were not informed, showing that vaccination was well-publicized. This educational technique should be re-used in all villages during coming catch-up tetanus collective immunizations in Cambodia, mostly in urban contexts where coverage during these sessions is lower. Video is still the best method in rural context if some education is also provided to the audience. According to the WHO schedule, the interval between two catch-up tetanus sessions should be extended to over a year to be able to give booster shots to women who already received three or more tetanus doses. Vaccination of schoolgirls is significantly easier to achieve with the help of the teachers. Vaccinating women aged over 45 should be encouraged as they are at risk of tetanus even in developed Asian countries.