Diagnosis of septic loosening of hip endoprosthesis with antigranulocyte scintigraphy (AGS) was analysed. Twenty-one hip prostheses were studied using laboratory tests and, in cases of elevated values, three-phase bone scan (BS) and AGS. Elective SPECT/CT scans were performed. Histologic and microbiologic exams verified the diagnosis. The AGS analysis revealed sensitivity, specificity and accuracy of value 1, while positive and negative predictive values were also 1. BS showed sensitivity of 1 and specificity of 0.33. In three cases, SPECT/CT scans corroborated the AGS interpretation. This diagnostic algorithm proved effective in the detection of septic loosening of hip prostheses. AGS can be avoided without risk of infection being overlooked.