The objective of this seroepidemiological survey was to estimate seroprevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) specific antibodies (IgM and/or IgG) in Portugal in May-July 2020. The seroprevalence of SARS-Cov-2 infection (positive for IgM and/or IgG) was 2.9% (CI95: 2.0 - 4.2%). Our results support extend limited extent of infection by SARS-CoV-2 in Portugal due to early lockdow...