Nowadays, computer interaction is mostly done using dedicated devices. But gestures are an easy mean of expression between humans that could be used to communicate with computers in a more natural manner. Most of the current research on hand gesture recognition for Human-Computer Interaction deals with one-handed gestures. But two-handed gestures can provide more efficient and easy to interact with user interfaces. It is particularly the case with two-handed gestures we do in the physical world, such as gestures to manipulate objects. It would be very valuable to permit to the user to interact with virtual objects in the same way that he/she interacts with physical ones. This paper presents a two-handed gesture database to manipulate virtual objects on the screen (mostly rotations) and some recognition experiment using Hidden Markov Models (HMMs). The results obtained with this state-of-the-art algorithm are really encouraging. These gestures would improve the interaction performance between the user and virtual reality applications.