Regression rate of CIN 1 (LSIL) can reach 85%. The purpose of this study was to investigate retrospectively pathology specimens in CIN 1 cases who delayed treatment > 2 years despite the persistence of the lesion. One hundred and fifteen women diagnosed with CIN 1 were separated in two groups as follows: A) 92 women who underwent ablative treatment within three months after the completion of two years; B) 23 women who delayed ablative treatment for a mean interval of > 1 year after the completion of two years. Exclusion criteria were normal cytology and colposcopy results within the completion of two years. The chi-square, t-test and Kaplan-Meier method were used for analysis. Persistence of LSIL lesions was observed in 84% of the first group and persistence or regression of the lesion in 78% of the second one. The study suggests the possibility of prolongation of the observation period after LSIL diagnosis. Prospective studies with close follow-up are needed for final conclusions.