Background Diabetic retinopathy is the most common microvascular complication of diabetic of diabetic mellitus. It is the leading cause of blindness among the age working group. The disease is usually diagnosed in advanced stages due to lack of facility and specialist eye care services. Methods This is a Crossectional clinic-based comparative study. The study determined the validity of Portable Eye Examination Kit (PEEK) in grading diabetic retinopathy at Kilimanjaro Christian Medical Centre eye clinic in northern Tanzania. Consecutively sampling used to enrol diabetic patients attended KCMC eye clinic. Results The overall exact agreement of PEEK and Topcon between the two examiners in grading DR was 80% and 83% for examiner one and two respectively. The simple kappa score for examiner one was 0.73 (SE: 0.04) and 0.77 (SE: 0.04) for examiner two. The sensitivity was greater than 80% for grading of all stages of DR except PPDR where it was 55.8%. The specificities were all greater than 90% except for BDR. Based on diabetic macular edema, kappa score is 0.83 (SE: 0.05) for examiner one and 0.90 (SE: 0.05) for examiner two. The agreement is 89% and 94% for examiner one and two respectively. Conclusion With these findings of the study, PEEK has demonstrated a good capability for detecting DR changes. It has the potential to be a useful tool for screening of diabetic maculopathy and diabetic retinopathy. Keywords Portable eye examination kit; Diabetic retinopathy; Tanzania