The aim of the study was to evaluate the relationship between physical activity and sexual function in women with type 1 diabetes mellitus (T1DM). The study group consisted of 171 women with T1DM. All the participants voluntarily filled out anonymous questionnaires. Women who were sexually inactive or had some psychological, psychiatric, or endocrine diseases were excluded from the analysis. The scores about sexual function were obtained using a Female Sexual Function Index (FSFI) questionnaire. Results equal to or below 26 points indicate clinically significant sexual dysfunction. Physical activity was measured by the International Physical Activity Questionnaire (IPAQ). Participants were divided into two groups depending on the Metabolic Equivalent of Task (MET-min/week) score with a cutoff point 3000 MET-min/week. Results above 3000 points indicate higher physical activity in woman. There were statistically significant differences in lubrication, orgasm, pain, satisfaction, and total score of FSFI. A positive correlation was revealed between results in total FSFI score and MET-min/week score (Rs = 0.18, p = 0.016). Univariate logistic regression does not show significant associations, but the multivariate logistic regression model shows an association between the MET-min/week and the total FSFI score. The higher the MET-min/week score, the higher the FSI score, and thus better sexual function.