As part of an ongoing project involving a large cohort in the Khon Kaen Province in the North-east of Thailand,a total of 236 women who had tested positive for a Pap smear at the initial recruitment and advised to seek mdicalattention were followed up after a mean period of 3.1 years. The 204 individuals who could be contacted wereinterviewed to determine treatments received and underwent a further Pap smear as well as colposcopy in 179 ofthe cases. On clinical advice, biopsies were also taken from 32 of these. Only 15% of the total of 204 had actuallyreceived therapy, the majority undergoing surgery (self-reported). Possible positive Pap smear results were obtainedfor 23.5%, with 6.4% having high grade squamous intraepithelial lesions (HGSILs) or squamous cell carcinoma(SCC) (one case). Comparison of the different testing modalities demonstrated 5.6% false negatives and 16.2false positives for the Pap smear with colposcopy as the gold standard. Compared with biopsy findings, therewere 21.8% and 40.6% false positives with Pap and colposcopy, respectively, but no false negatives. The presentresults point to good efficacy for the initial screening, since only 0.5% of the total population developed an SCC.However, judgement as to therapy should depend on a biopsy since there were considerable false positives withthe other two modaltites employed.