The number of cases diagnosed with neoehrlichiosis in Stockholm has increased over the last years. PCR analysis is needed for the detection of the intracellular bacterium Neoehrlichia mikurensis. The real number of cases in the area is unknown since the specific PCR for N mikurensis is not routinely included in the workup for unknown fever in Stockholm. By describing three cases, we want to increase the awareness of neoehrlichiosis among clinicians. Symptoms of prolonged fever, myalgia and thrombosis among immunocompromised patients should raise the suspicion of neoehrlichiosis and the specific PCR analysis should be performed. The diagnosed patients were all treated with doxycycline; the fever disappeared within a few days, and clinical improvement was observed. After treatment no relapses were noticed, despite immunological deficiencies in the patients.