We report on the structural modifications of carbon nanotubes (CNT) by laser irradiation. In particular, we investigated the transformation of CNT by using Nd:YAG laser operating at 266 and 1064 nm with different energy fluences and number of pulses. After 15 pulses of 266 mn laser irradiation with a laser fluence of 80 and 60 mJ cm(-2), transformation of CNT into sub-micron size plates and cauliflower type aggregation of carbon deposits, respectively, were observed. At a fixed laser fluence of 400 mJ cm(-2) (1064nm) transformation of CNT into carbon mass protrusions with progressive sharper aspect ratio was obtained by increasing number of laser pulses. Our investigations demonstrate that a selective area transformation can be controlled by the laser fluence and number of pulses.