Practicum is an important aspect of the counsellor education programme which is aimed at helping student counsellors develop practical skills and other qualities required for professionalism. The study investigated the impact of counselling practicum on trainees in University of Ilorin, Nigeria. The descriptive research design was adopted for the study. The population of the study consisted of all student counsellors in the Department of Counsellor Education, University of Ilorin. The simple random sampling technique was used to select 250 respondents selected from both the full-time undergraduate and postgraduate programme. A researcher developed questionnaire tagged "Impact of Counselling Practicum Questionnaire (ICPQ)" was used to gather data from the respondents. The questionnaire was validated by lecturers in Counsellor Education Department University of Ilorin and was also subjected to reliability test using a Pearson's Product Moment Correlation formula and a reliability coefficient of 0.68 was obtained. The data obtained were analysed with percentages, mean ranking and t-test statistic. The findings revealed that the counselling practicum has high impact on counsellortrainees. For instance, it assists trainees to; develop self-confidence in relating with clients, learn how to apply counselling skills maximally, and discover their strengths as student counsellors. A significant difference was found on the impact of counselling practicum on trainees based on respondent's level of education but no significant difference was found on the basis of gender. The implication is that trainees at different level need practicum experience to achieve professional development. It is recommended that undergraduate and postgraduate counsellortrainees, irrespective of gender, should be assisted to develop requisite skills, ethics, and values of carrying out their professional roles optimally in the counselling profession.