Glu-NH-CO-NH-Lys-(Ahx)-[Ga-68(HBED-CC)], abbreviated as Ga-PSMA, is a novel radiotracer undergoing evaluation for PET/CT imaging of prostate carcinoma. Its major advantage is the sensitive detection of lesions even at low prostate-specific antigen level and high target-to-background ratios obtained in metastatic lesions, which is better than that obtained with F-fluoromethylcholine. We present the case of a 28-year-old man with poorly differentiated prostate carcinoma with neuroendocrine differentiation, whose lesions did not show significant Ga-PSMA localization. As literature on utility of Ga-PSMA PET/CT for imaging prostate carcinoma grows, it is important to be aware of potential false negatives that could influence study results.