Inventive step is a fundamental requirement that must be fulfilled in order to grant patents and utility models. It means that an invention must not prove obvious to an ordinary expert skilled in the art. However, the level of inventive step required for patents is greater than that required for utility models, since in the latter case, the invention must not prove very obvious to an expert.

In Europe, something is generally considered to be obvious if all the characteristics of the invention proposed may be obtained as a result of probable combinations of two previously existing inventions, taking into account that this would have occurred naturally to an expert, in view of these two background documents and that, in order to achieve a technical effect, one can simply combine them to obtain the invention proposed. If this process requires three or more documents to be combined, it is no longer considered obvious.

In other territories, the interpretation of inventive step may be more subjective or difficult to determine.