Diagnosing acute hepatitis C is still difficult. The disease is frequently asymptomatic and there are no specific diagnostic tests. Most frequently, diagnosis is based on anti HCV antibodies serum conversion and, more rarely, on a double serum conversion (initially HCV-RNA undetectable by RT-PCR, subsequently positive and serum conversion for HCV antibodies determined by EIA and RIBA techniques). Evolution of HCV infection is determined by the intensity of immune response, type of secreted cytokines and persistence of specific HCV T lymphocytes response. Patients achieving viral clearance present an early, strong and multi specific T lymphocyte response. Spontaneous viral clearance rates are highly variable between 10-60%. It is currently recommended to delay start of treatment for 2-4 months after onset and this delay does not compromise chances of achieving sustained virologic response. It is necessary to repeat viremia 6 months -1 year after spontaneous viral clearance due to the possibility of viral replication restart. There are currently no firm guidelines regarding treatment regimens, treatment duration and timing of its initiation. Monotherapy with high dose interferon alpha or peg-interferon for 6 months is recommended. Although important progress has been achieved in acute hepatitis C understanding, research continues to improve treatment regimens and to clarify mechanisms of viral clearance.