ABSTRACT The lecture allows very little interaction and feedback from the students. Class Response System (CRS) can have a catalytic effect on teaching with lecture environments moving from silence and passivity towards dialogue and interaction. The present study was conducted to see the effectiveness of increasing the attentiveness of students in classroom theory lectures and to study the students’ perception of effectiveness of CRS in improved learning outcome. CRS was used in the lecture classes of Public Health for the undergraduate students of MD program of College of Medicine. Students anonymously clicked answers for the questions displayed on the screen. Correct answers were discusses with instant feedback after the CRS session. Likert scale was used to assess students’ opinion on the effectiveness of CRS for better learning. The average percentage of correct responses in the CRS sessions was 77.15 ±10.34. Statistically significantly more number of students got higher grades when CRS was used. 87% of students agreed that it aroused their interest in the class and 79.7% said that it made them more attentive during the lecture. 79.1% agreed that it encouraged discussion over the wrongly answered questions. CRS made the students attentive in the class and created a platform for the students to interact with the teacher and clarify their concepts in the class itself. It helped them in memorizing the key points in the lecture which helped them to recall it even when they studied on their own thereby helping them to get better grades in exams. Keywords: Class response system, concentration, clickers, perception, students.