The aims of the present study were to explore the effects of two different types of task conditions (topic choice vs. no choice) on the quality of written production in a second language (lexical complexity, syntactic complexity, and cohesion) and to investigate the effects of these two different task conditions on task motivation. This research was conducted by means of a task motivation questionnaire and a collation of the writings of 31 Korean college students learning English as a foreign language. The data was analyzed using Coh-Metrix 3.0. The major findings were as follows: 1) The writings of participants in the topic choice condition were better than those in the no-choice condition in terms of lexical sophistication and temporal cohesion. However, participants’ written production in the no-choice condition was better than that in the topic choice condition in terms of syntactic complexity. 2) The participants’ task motivation levels were higher for the perceived choice domain in the topic choice condition than in the no-choice condition. These findings should help L2 writing instructors, materials developers, and researchers to design L2 writing instruction with a focus on written production specifically for Korean college-level learners.