The main purpose of this thesis is to study the aspectual complements of the aspectualizers begin and start. Aspectualizers are verbs that give aspectual readings to the sentence. I started with a summary of Freed''s (1978) analysis. In this summary, semantic differences among seven aspectualizers that take to V and V-ing complements were explained. The semantic distinction between to V and V-ing was also discussed. Following the summary, a brief research on aspectual complements was conducted. Based on Freed''s analysis, I first examined the difference in meaning and in frequency of occurrence between the to V and the V-ing complement of the two aspectualizers. My research revealed some interesting problems that Freed failed to address. These problems blur the difference between the to V and the V-ing complement of begin and start that Freed claims. Through the research, however, I failed to pinpoint the significant difference, too. More research on this issue should be done in the future.