The study investigated how task types such as input or output could affect Korean EFL learners’ vocabulary learning at both short- and long-term periods after treatment. Forty two college students in Korea were randomly assigned to one of the four tasks. Based on Involvement Load Hypothesis, each task induced the same or different involvement loads: Read without glossary (Input), Gap with glossary (Input & Output), Gap without glossary (Input & Output), and Sentence and write (Output). Receptive and productive vocabulary knowledge was measured right after the treatment and a month later. The output-oriented tasks were found to be more effective than the input-oriented tasks regardless of type of vocabulary knowledge. The current study concluded that modalities such as input or output other than task-induced involvement load can contribute to Korean EFL learners’ vocabulary learning. The pedagogical discussion will be made at the conclusion.