Contextual interference is one of the instructional methods for several skills. The aim of this research was to determine the effects of interference before performance and interference during performance on the acquisition and retention of generalized motor program and parameter in basketball skills with an emphasis on the examination of contextual interference hypotheses and self-regulation learning theories. In interference before performance, self-practice schedules is generated (self-regulation effect) and interference during performance, experimenter-imposed practice schedule is generated (contextual interference effect). For this purpose, 120 students of Yazd University (age range 19-21 years old) who had no prior experience in basketball skills volunteered to participate in this study. Participants were randomly assigned to 10 groups (each 12 subjects); 5 groups practiced with generalized motor program (dribble, chest pass and free throw skills) and 5 groups practiced with parameter (free throw from different distances) in practice schedules (blocked, random, serial, self-regulated and yoked to self-regulated). To collect data, throw and pass test (AAHPERD basketball test) and dribble test (Johnson basketball test) were used. After the pretest, in the acquisition phase, subjects took part in 5 training sessions including 45 trails per session (15 trails each block) for 5 days. After 48 hours, they participated in retention test with 15 trails (5 trials each task). The data were analyzed by one-way ANOVA, factor analysis of variance with repeated measures, LSD and Duncan post hoc tests. Results showed a significant difference among practice schedules in acquisition and retention phases of generalized motor program, that is, the effect of contextual interference was observed in this program (p<0.05). Also, there was a significant difference among the schedules in acquisition and retention phases of parameter, that is, controlling the design of practice has a positive effect on learning (p<0.05). Thus, the results suggested that during learning process, the effect of interference before performance was more important than during performance.