Advanced parental age is a risk factor for chromosomal abnormalities in their offspring. Trisomy X or Triple X syn- drome has previously been reported with advanced maternal age. Here we report two (2) cases of Trisomy X with paternal age as risk factor. Generally, Trisomy X individuals show variable physical and psychological manifesta- tions. However, both cases reported here have advanced paternal age as a risk factor; 55 years old (46 years old at conception) for Case 1 with patient having right eye squint, beaked nose, Posterior Misalignment Type Ventricular Septal Defect (PMVSD) and small Patent Ductus Arteriosus (PDA) with failure to thrive and 49 years old (45 years old at conception) for Case 2 with speech delay and protruding tongue. In view of that, advanced paternal age could possibly contribute the accumulation of de novo mutations in germ line mosaicism.