Distended fetal bladder, also known as fetal megacystis, usually points to lower urinary tract obstruction (LUTO) which is most commonly caused by posterior urethral valves (PUV) in the male fetus. We present a short case-series of fetal megacystis without oligohydramnion where primary vesicoureteral reflux (VUR) was the leading aetiology. These cases also displayed a high rate of kidney dysplasia with early-onset renal dysfunction. By contrast, late-onset diagnosis of isolated megacystis, i.e without significant renal parenchymal or upper urinary tract abnormalities, had a surprisingly benign postnatal course with spontaneous resolution after birth. Our case series also display the associated risk for extra-renal malformations and specifically neuro-cognitive developmental abnormalities which should be sought on genetic and imaging evaluation.