目標：全民健保提供30歲以上婦女每年一次免費子宮頸抹片檢查，卻有相當高比率之婦女長時間未曾受檢，有別於過去剖面式之問卷調查研究，本文藉由個體時間序列資料(panel data)實證分析，探討需求面(如社經)及供給面(如醫療資源)因子如何影響受檢情形。方法：利用國家衛生研究院承保抽樣歸人檔，擷取1997/01/01起滿30歲以上婦女且1997-2000年未曾間斷投保者20,608人為固定世代樣本，利用廣義估計方程組(Generalized Estimating Equations, GEE)分析影響因子。結果：(1)未接受年度檢查與四年未曾受檢之影響因子一致(2)未受檢之風險(勝算比)：無家戶綜合所得稅資料者為高所得者之1.2～1.3倍，於公所投保者則為軍公教人員之1.5～1.6倍，山地離島為大城市之1.5倍；鄉鎮之醫師密度尚無法證明為影響因子。結論：社經因子是影響受檢情形之重要因素，低社經地位者比高社經地位者更有可能長時間從未受檢。醫療資源雖非影響因子，但設籍山地離島之婦女比大城市者更有可能長時間從未受檢。政策上宜先對長時間從未受檢者提高受檢情形。

　　　　　Objective: The National Health Insurance (NHI) program in Taiwan has provided free annual Pap smear screening for women aged over 30 since July, 1995. However, the rate of Pap smear screening is still low. In this study, we studied how demand and supply side factors such as SES and medical resource availability influenced Pap smear screening patterns under the NHI in Taiwan between 1997 and 2000. Method: Instead of using cross-sectional survey data, we adopted a fixed cohort sample (N=20608) through employing the NHI claim and administration files. The method of Generalized Estimating Equations was conducted to estimate the screening pattern over time. Factors associated with receiving no Pap smear screening during the 4-year study period were also examined. Results: Women whose income was below the tax return filing requirement were 1.22 times and 1.28 times more likely to have no routine screening and be unscreened for the entire study period than those at upper income levels. It seems that the availability of medical resource had a weaker influence on screening behavior. However, women living in rural towns were less likely to conduct routine screening and more likely to be unscreened for 4 years than those living in urban towns. Conclusions: Our results indicate that 52% of women were not screened over the 4-year period. Attention should be focused on these high- risk women and lower social economic status groups.