BACKGROUND: Leptospirosis is an important zoonosis worldwide, nevertheless is often poor recognized in non tropical settings. In Thailand is becoming an emerging disease and Chiang Mai could become a popular spot to acquire the disease amongst travelers. METHODS: We describe three cases of imported leptospirosis undifferentiated fever after travelling to Thailand during the summer of 2015 diagnosed at two Spanish hospitals. RESULTS: Our three patients probably acquired leptospirosis while swimming in freshwater around Chiang Mai, a Thailand's northern region with moderate incidence of leptopirosis. Travelers had normal white blood cell counts and low platelets, suggesting leptospirosis after ruling out other imported diseases such as malaria, dengue or typhoid. CONCLUSION: As recent findings point out, low platelets and normal white blood cell counts are clinical features that could help the clinician to suspect Leptospirosis infection. It should be always considered as a cause of fever, particularly if travelers come from a tropical country and have had contact with water or flooding, especially during rainy season.