Purpose/Introduction: To systematically review studies which compare transperineal ultrasound with defaecatory imaging. Methodology: The systematic review was performed in accordance with PRISMA guidelines. Pubmed, Medline and Cochrane databases were searched. 14 studies comparing transperineal, translabial or introital ultrasound with defaecatory imaging were included. One study that directly compared sonographic findings with defaecation MRI. The main measured outcomes were the accuracy and agreement for the detection of rectocoele, enterocoele, sigmoidocoele, peritoneocoele, intussusception, perineal descent and dyssynergy on transperineal ultrasound compared to defaecation proctography. Results: Rectocoele detection between transperineal ultrasound and proctography was poor to excellent, specificity 67 to 100% and sensitivity 29 to 88.9%. Enterocoele (sigmoidocoele or peritoneocoele) detection was good to excellent, specificity 92 to 96% and sensitivity 64 to 80%. Intussusception/ rectal prolapse was poor to excellent, specificity 84 to 100% and sensitivity 22 to 100%. Accuracy of transperineal ultrasound is higher for larger rectocoeles, and higher grades of enterocoeles or intussusception. Three of the four studies which examined the anorectal angle found no significant difference in its measurement on both modalities. Conclusion/s: Transperineal ultrasound is a suitable screening tool for obstructive defaecation so defaecatory imaging may be unnecessary in some. The technique and interpretation require refinement and standardisation. The true clinical relevance of findings on transperineal ultrasound will only be understood once sonographic findings are compared with clinical symptoms.