Task-based language teaching comprises both a novel language teaching approach and a burgeoning area of study in the field of second-language acquisition. This study investigated the effects of task type and planning conditions on the accuracy of learners' oral performance during pre-task planning. Eighty intermediate EFL learners were assigned to four task conditions: individual-planning personal task, individual-planning decision-making task, group-planning personal task, and group-planning decision-making task (n= 20). Individual task performances were scored for accuracy prior to the treatment sessions. During the treatment sessions, the participants completed the tasks under different planning conditions. Results of statistical analyses revealed that pre-task planning conditions and the task type are effective in enhancing the accuracy of learners' oral production. The findings lend support to the view that there are advantages in selecting and implementing appropriate task-based conditions to develop the accuracy of language learners' oral performance. The implications for task-based language teaching are explained and some suggestions for further research are offered.