El proceso penal romano ha oscilado entre tendencias al sistema acusatorio y al inquisitorio. Tradicionalmente se ha considerado a las quaestiones perpetuae como manifestación de un sistema acusatorio; y de uno inquisitorio a la cognitio extraordinem. Esta visión ha sido revisada modernamente, y se sostiene que en la cognitio hubo continuidad del método acusatorio precedente. Pero varios y numerosos son los puntos controvertidos y sin definitiva solución. En este trabajo se sostiene la teoría ecléctica, que, por lo demás, es la admitida en el proceso penal moderno. The Roman criminal procedure has ranged between tendencies to the accusatory system as well as to the inquisitorial system. Traditionally the quaestiones perpetuae has been considered as a manifestation of an accusatory system and cognitio extraordinem as a manifestation of an inquisitory system. This view has been currently reviewed and it is stated that in cognitio there was continuity in the previous accusatory method. However, there are several and different points which are argued and without a definite solution. This work asserts the eclectic theory, which is, in fact, admitted by the modern criminal proceedings.