Prostate cancer is one of the commonest cancers in men. The purpose of this work was to compare ‎between ‎intensity-modulated radiotherapy (IMRT) versus three-dimensional conformal radiotherapy ‎‎(3D-CRT) planning in patients with prostate cancer using 6-MV and 15-MV photon energies. Twenty ‎patients with localized prostate cancer were planned on Xio treatment planning system. Four treatment ‎plans were generated for each patient. IMRT whether 6 or 15 MV beam was slightly better in terms of ‎target coverage but not significant (p>0.05) in comparison to 3D-CRT in both beam energies. IMRT ‎was better than 3D-CRT in terms of organs at risk (OARs) sparing and conformity index (CI) in both 6 ‎and 15-MV whereas 3D-CRT in both 6 and 15-MV yielded better homogeneity index (HI) compared ‎to IMRT 6 and 15-MV. The number of monitor units (MU) increased in IMRT compared to 3D-CRT. ‎Also,‎‏ ‏MU increased in low energy compared to high energy whether in 3D-CRT or IMRT (p<0.05). ‎When IMRT 6-MV and IMRT 15-MV were compared, no significant difference was found in terms of ‎target coverage and OARs except the rectum was better in IMRT 6-MV compared to IMRT 15-MV. ‎IMRT 6-MV technique should be prioritized when user has options for treatment and then 3D-CRT as ‎a second line when the former is not available. The choice of the energies (6 and 15MV) used with ‎‎3D-CRT depend largely on patient's body geometry while the use of high energy IMRT 15-MV is not ‎recommended.‎