The goal of this research is to determine the relevant factors that aid in the acquisition of the perfective aspect in Russian. Results confirm the findings of previous research, which say that aspect is not learned as a uniform category, but rather interrelates with the acquisition of Aktionsarten. This study focuses on the factors responsible for the difference in the rate of the acquisition of two complementary Aktionsarten in the perfective aspect: telic verbs (verbs including a result/goal of the denoted event) and ingressive verbs (verbs including the beginning of the event). Since the usage of Aktionsarten strongly depends on the surrounding discourse, two experiments that varied in their discourse complexity were conducted. One study looked at the production of isolated utterances (thirty-nine children aged 3;0 to 6;11) and the other study focused on complex texts (fifty-two children aged 3;0 to 6;11). It was found that while telics are used independently of discourse context, ingressives depend strongly on contextual information. These results suggest that discourse complexity and narrative competence define the acquisitional process for ingressives, yet are irrelevant in the acquisition of telics.