Proponents of Processing Instruction (VanPatten, 2005) claim that learners benefit most when presented with both referential and affective structured input activities. Following a classic pretest-posttest design, the present study investigates the role of these two types of activities on the learning of the Spanish subjunctive. Groups differed only with respect to the types of activities completed during practice: (1) affective activities only, (2) referential activities only, or (3) referential activities followed by affective activities. All groups showed a significant improvement in performance on recognition and interpretation tasks, suggesting that both types of activities, either in isolation or combined, may be equally beneficial to learners. All practice conditions experienced a decline in performance over the span of two weeks, but delayed posttest scores were still significantly higher than pretest scores, indicating that some of the gains from instruction were maintained over time. Additionally, in the case of interpretation items, results revealed that the two groups that engaged in affective activities were able to better maintain learning gains over the span of two weeks than the group that completed only referential activities. Findings are discussed in relation to the role of task-essentialness in structured input practice. (Contains 2 figures and 2 tables.)