Purpose <p>This systematic review and meta-analysis aimed to determine whether home-based preoperative physical activity (PA) influenced the incidence of postoperative complications (PCs) in patients who underwent oncologic surgery.</p> Methods <p>A comprehensive literature search was conducted using five electronic databases. Full articles with observational designs that compared by preoperative PA or PCs were included. The primary outcome was some type of PC, and a meta-analysis was performed to determine the impact of preoperative low PA on the incidence of PCs. Sub-analysis was performed to identify subgroups based on the severity of the PCs and the cancer site.</p> Results <p>Eight studies were included in the analysis. Low preoperative PA was associated with all PCs (odds ratio [OR] = 2.42, 95% confidence interval [CI] = 1.44 to 4.07) but not with severe PCs (OR = 1.93, 95% CI = 0.51 to 7.37). In a subgroup of patients with gastrointestinal cancers, low preoperative PA was associated with all PCs (OR = 3.44, 95% CI = 1.63 to 7.26) and severe PCs (OR = 2.93, 95% CI = 1.30 to 6.58).</p> Conclusions <p>This systematic review and meta-analysis revealed that patients with low preoperative PA undergoing oncologic surgery, particularly those with gastrointestinal cancers, are more likely to develop PCs. A definitive conclusion could not be reached, however, due to the limited number of studies exclusively examining this relationship in cancer patients.</p>