After a brief introduction about rickettsioses, we analyse Mediterranean Spotted Fever (MSF) in Portugal, and review Portuguese medical literature. We focussed on the seasonal summer pattern of the disease. MSF is very frequent in Portugal, nearly 1,000 cases are reported every year and young age groups are the most afflicted. Although usually regarded as a benign condition, MSF has emerged as a potentially lethal disease in recent years. The clinical presentation is protean, but usually suggestive enough to allow a clinical diagnosis. The complications are well documented, elderly and people with chronic debilitating diseases being the most affected. Q fever is also endemic in Portugal, although with more modest numbers (about 50 cases a year). Serological studies, however, suggest a higher incidence, probably because the disease is unfamiliar to many clinicians and, as such, it is difficult to diagnose and, consequently, then an important number of subclinical or self-limited cases. In Portugal, fever with hepatic involvement is the most common clinical presentation. Other less frequent clinical forms are atypical pneumonia and CNS involvement. Chronic Q fever is a rare condition.