We re-evaluated acute and early-late toxicity-related factors among pre-pectoral immediate tissue expander/implant (TE/I) breast reconstruction (BR) unselected, first-era, cases, including previous breast radiation treatment and post-mastectomy radiation therapy (PMRT). A retrospective analysis of 146 (117 therapeutic and 29 prophylactic) pre-pectoral reconstructions, between 2012 and 2016, considered patient-related (age, body mass index [BMI], smoke-history, comorbidity, BRCA mutation), and treatment-related characteristics (previous irradiation, axillary surgery, PMRT, pre-and postoperative chemotherapy, endocrine therapy, and target-therapy). Safety was evaluated as acute and early-late complications, and TE/I failures. At multivariate analysis of the 146 cases (117 patients submitted to BR) a significant factor related to acute toxicity was: BMI ≥ 25 (31.3% [≥ 25] vs 8.8% [< 25]; OR 4.44, 95% CI 1.56-12.6; p = 0.003), while previous breast surgery on ipsilateral side presented a borderline significance (31.6% [previous surgery] vs 7.4% [no previous surgery]; OR 3.74, 95% CI 0.97-14.40; p = 0.055). Factors significantly related to TE/I failure were: current or previous smoking exposition (13.8%[smokers] vs 2.6% [non-smokers]; OR 7.32, 95% CI 1.37-39.08; p = 0.02) and preoperative chemotherapy (18.8% [yes] vs 3.5% [no]; OR 8.16, 95% CI 1.29-51.63; p = 0.026). At 4-year median follow-up, 3 deaths, 5 locoregional recurrences, and 14 distant metastases occurred. Immediate pre-pectoral BR is safe and effective, with low rates of acute and early-late complications. BMI and previous breast surgery were related to higher complications but not failure; smoking and preoperative chemotherapy were related to TE/I explant. Previous RT and PMRT were related neither to early-late toxicity nor failure.