Abstract: The instructional value of rubrics for promoting student learning and aiding teacher feedback to student performance has been studied extensively. This paper investigates the effects of rubrics in the ESL context; specially speaking and writing task assessment. Forty eight students attending an English Language undergraduate program at BAU, Mymensingh grouped into two as controlled group and experimental group participated in this study. Students’ performance at pre-test was compared with that of the post-test (with prior knowledge of rubrics only for experimental group). Statistical analysis paired sample t-test was used to compare the performance of the students on the use of rubrics at their posttest. Results showed that the rubric was perceived as useful for fostering the students’ speaking and writing development by guiding them through the stages of goal-setting, planning, self-monitoring and self-reflection. The paper also reports a significant impact of the rubrics use on students’ self-assessment.