The primary objective of the thesis will be to focus on patent protection of software under the European Patent Convention, by analyzing the different approaches that the European Patent Office has taken into consideration since the mid-1980s. These approaches are derived from the different decisions that emanate from the Technical Boards of Appeal of the European Patent Office. The thesis will examine the most relevant decisions illustrating the juridical tendencies and basis that have been utilized to decide over the patentability of computer programs. The analysis will conclude with the latest approach taken by the Technical Board of the European Patent Office. The study will examine the patentability requirements of inventions in general established within the European Patent Convention. Sources that will be utilized to carry out this research will include case law, legislation, specialized legal commentary; journals and books. The present study sustains that computer programs may be patented as long as they comply with all the general requirements of an invention prescribed under the European Patent Convention together with the condition established by case law called the technical character requirement. Nevertheless, due to the fact that the Technical Boards of Appeal are not bound by previous case law, the current position could keep evolving as it relies on the stance of  the European Patent Office on patentability of computer programs which is seems to be influenced by the changes in the technological world