This thesis reviews the literature on “new terrorism,” to be differentiated from the “old terrorism.” The study tests two hypotheses. First, has an increase in religiously inspired terrorist groups led to an increase in terrorism's lethality? Second, does suicide bombing as a tactic explain the increased lethality of “new terrorism”? The study demonstrates three findings. First, it was found that religiously inspired terrorist groups are more lethal, though not more indiscriminate. Second, that suicide bombing has had a significant effect on the number of terrorist related fatalities. And, third, that non-religious suicide bombing is more lethal than its religious counterpart. To test these hypotheses I used Ordinary Least Squares Regression and data provided by The International Policy Institute for Counter-Terrorism.