<b><i>Aim:</i></b> This study aims to quantify longitudinal changes in waist circumference (WC) among adults aged 45-64 years in Germany. <b><i>Methods:</i></b> Data of 15,444 men and 17,207 women from one nationwide and six regional prospective German cohort studies were analyzed. The sex-specific mean change in WC per year of follow-up was assessed for each study separately. Findings from the cohort-by-cohort analysis were combined by applying meta-analytic methods. Progression to central obesity (WC ≥ 102 cm in men and ≥ 88 cm in women) within a standardized period of 10 years was described for each study. <b><i>Results:</i></b> The estimated mean change in WC per year of follow-up for all cohorts combined was 0.53 (95% confidence interval 0.29-0.76) cm/year for men and 0.63 (0.48-0.77) cm/year for women, but varied between the included studies. Within 10 years, about 20% of individuals with low WC (<94 cm in men; <80 cm in women) and about 50% of individuals with intermediate WC (94-102 cm in men; 80-88 cm in women) progressed to central obesity. <b><i>Conclusion:</i></b> The increase in mean WC with aging along with a profound increase of central adiposity is obviously and may have several adverse health effects. Obesity prevention programs should also focus on abdominal obesity.