Leptospirosis has a highly variable clinical presentation, which may be related to different infecting serovars, host factors, or a combination of these. This study investigated retrospectively 34 consecutive patients with serologically confirmed leptospirosis admitted during the period 1992–2002. On admission, the most frequent symptoms were fever (100%), headache (75%), myalgia (55%), arthralgia (45%) and vomiting (39%). Pertinent laboratory findings included lymphopenia (85%), thrombocytopenia (75%), elevated liver enzymes (87%) and renal abnormalities (proteinuria, 77%; haematuria, 58%; elevated serum creatinine, 53%). The study confirmed the variable clinical and biological symptoms of leptospirosis, and indicated that lymphopenia is a common feature of leptospirosis cases.