Various types of drugs are being used to treat patients with chronic hepatitis B infection. However, these treatment modalities are not without side effects, which may result in decreased patient adherence. Entecavir is an oral reverse transcriptase inhibitor, which is widely used in patients with hepatitis B. Although headache, fatigue and nausea are well-documented side effects of entecavir, its sexual side effects have not been reported yet. We here report on two male patients with chronic hepatitis B infection who reported decreased libido under entecavir treatment.