The study was conducted to examine the challenges associated with mentoring of preservice teachers in selected Senior High Schools in the Kumasi Metropolis of the Ashanti Region. The objectives of the study were to determine the processes involved in mentoring teacher trainees in the study area, ascertain the factors that promote effective mentoring of teacher trainees in the study area and to identify the challenges associated with the mentoring process. Descriptive survey design with closed ended questionnaire was used as the research instrument for the study. The targeted population of this study comprised all the mentors and mentees of Kumasi High Schools and Anglican Senior High School. Purposive sampling technique was therefore used to select all the 164 mentors and mentees for the study. The study found among others that the processes involved in mentoring teacher trainees are relationship building and exchanging information. Factors that promote effective mentoring of teacher trainees are listening actively in the mentoring relationship, and encouraging and inspiring mentees. Challenges associated with the mentoring process are selection and training of mentees and mentor not being the expert in the subject area of mentees. Based on the findings, it is recommended that the Ghana Education Service should see to it that only mentors who are experts in the study area of the mentees should be assigned to the mentees.