Objectives To investigate the efficacy and safety of pegfilgrastim administered on the day of chemotherapy completion (same day) versus at least 1 day after chemotherapy (next day). Methods We searched relevant literature published before April 2020 from the following databases: Embase, PubMed, Cochrane databases and Web of science. Results One randomised controlled trial and 12 observational studies met all of the prespecified criteria for eligibility. The meta-analysis showed a significantly higher febrile neutropenia (FN) rate for the same-day group than that for the next-day arm in the first chemotherapy cycle (OR=2.56, 95% CI 1.19 to 5.48, p=0.02), and in all chemotherapy cycles (OR=1.54, 95% CI 1.29 to 1.84, p<0.00001). Results of subgroup analysis showed a higher FN rate in the same-day arm than in the next-day group for patients with breast cancer (OR=5.50, 95% CI 2.29 to 13.23, p=0.0001) and lymphoma (OR=1.53, 95% CI 1.00 to 2.34, p=0.05). The pooled analysis of studies on gynaecological malignancies showed that patients in the same-day group had a higher incidence of bone pain (OR=1.30, 95% CI 1.01 to 1.68, p=0.04) and a lower incidence of chemotherapy delay (OR=0.71, 95% CI 0.53 to 0.96, p=0.03) compared with the next-day group. Conclusions Same-day administration of pegfilgrastim resulted in increased incidence of FN compared with the next-day schedule. This is especially true for patients with breast cancer or lymphoma. These results do not support same-day administration of pegfilgrastim .