No written exams.They shortlist candidates by looking at many things of which USMLE scores is very important.Furthermore they give much preference to HMC interns and those who have worked earlier in HMC.So i strongly advise you to enroll in an attachment programme.
HMC is the only place in Qatar that provide Medical residency programmes.And sorry for replying so late as i was so busy and didn't open my QL account.