Purpose: To investigate the long-term safety (primary endpoint) and effectiveness (secondary endpoint) of the somatropin biosimilar Omnitrope®. Methods: PATRO Children is an ongoing, multicenter, observational, post-marketing surveillance study. Children who received Omnitrope® for any indication were included. Adverse events (AEs) were evaluated in all study participants. Auxological data, including height standard deviation scores (HSDS) and height velocity standard deviation scores (HVSDS), were used to assess effectiveness. In this snapshot analysis, data from the Italian subpopulation up to August 2017 were reported. Results: A total of 291 patients (mean age 10.0 years, 56.0% male) were enrolled at 19 sites in Italy. The mean duration of Omnitrope® treatment was 33.1 ± 21.7 months. There were 48 AEs with a suspected relationship to the study drug (as reported by the investigator) that occurred in 35 (12.0%) patients, most commonly headache, pyrexia, arthralgia, insulin-like growth factor above normal range, abdominal pain, pain in extremity and acute gastroenteritis. There were no confirmed cases of type 1 or type 2 diabetes; however, two patients (0.7%) had impaired glucose tolerance that was considered Omnitrope® related. The mean HSDS increased from − 2.41 ± 0.73 at baseline (n = 238) to − 0.91 ± 0.68 at 6.5 years (n = 10). The mean HVSDS increased from − 1.77 ± 1.38 at baseline (n = 136) to 0.96 ± 1.13 at 6.5 years (n = 10). Conclusions: In this sub-analysis of PATRO Children, Omnitrope® appeared to have acceptable safety and effectiveness in the treatment of in Italian children, which was consistent with the earlier findings from controlled clinical trials.