Purpose: Breast cancer (BC) patients’ (pts) management was affected by a global reorganization after Coronavirus disease 2019 (COVID-19). Our multicenter study aimed to assess the impact of COVID-19 on access to diagnosis, staging and treatment for BC pts compared to pre-pandemic. Methods: Medical records of all consecutive newly diagnosed BC pts referred to 6 Italian Institutions between March and December 2020 were assessed. Monthly access rate and temporal intervals between date of symptoms onset, radiological, cytohistological diagnosis and treatment start were analyzed and compared with 2019. Results: A reduction (25%) in newly diagnosed BC was observed compared to 2019 (666 vs 890). New BC pts in 2020 were less likely to be diagnosed with early stage BC (77% vs 83%, p 0 in 2020 vs 16.5% in 2019, p < 0.01) and fewer pts were asymptomatic at diagnosis in 2020 (54% vs 71%,p < 0.01). COVID-19 did not negatively impact in terms of access to diagnosis, staging and treatment. Time intervals between symptom onset and radiological diagnosis, symptom onset and cytohistological diagnosis, cytohistological diagnosis and treatment start were maintained or improved. However, less cases were discussed in multidisciplinary tumor meetings during 2020 (60% vs 73%, p < 0.01). Conclusions: Our data proved an alarming reduction of early stage BC associated with the COVID-19 crisis in 2020. Despite the upheaval generated by the pandemic, our study shed light on the effective performance delivered by Italian Oncology Departments to guarantee diagnostic-therapeutic pathways.