Abdominal ultrasonography is the procedure of choice to diagnose hydatid cysts caused by Echinococcus granulosus. Recently three-dimensional ultrasonography has become available for clinical application. We report a case of an atypical seronegative hydatid disease, in which the additional use of 3D-sonography improved the sonographic diagnosis, which was confirmed by a fine needle biopsie complicated by an anaphylactic reaction. In addition the potential advantage of 3D-ultrasonography in diagnosis and follow-up hydatid disease will be discussed, especially in the context of new alternative therapeutic options like chemotherapy with benzimidazoles or the percutaneous drainage by the PAIR procedure (puncture-aspiration-injection-re-aspiration).