The paper provides a comparative analysis ofthe minimum insurance period that entitles a person to the old-age pension in selected European countries, Canada and the United States. Based on the results, it presents the potential changes in the minimum insurance period in the Czech Republic. The subsequent analysis of the pension institution (ČSSZ) data file evaluates the impact of two possible variants of reforms of minimum contribution period for the pension entitlement of individuals in the time of their retirement with respect to both: men and woman. The following analysis provides a quantification of the impact of such changes on the balance of the Czech pension system.