This thesis aims to show the need to accept the aspect-oriented approach to software development as a new, advanced programming methodology which simplifies the development and maintenance of business information systems. There are some difficulties in using the conventional techniques of software development which are not completely solvable: code tangling which happens when one module contains the code for implementation of several functionalities at once, and code scattering which happens when multiple modules contain pieces of code to implement a single concern. Those problems are solved with AOP approach with introduction of aspects. To make the theory useful, it needs to be implemented. An AOP implementation consists of two parts: language specification (describes the syntax) and the language implementation (verifies the compliance with the syntax and translates the code in an executable form). The implementation is done by a new entity called the aspect weaver – using the weaving rules, it injects the aspect code into the basic code creating the final program. The aspect is the key unit (module) which performs the task of crosscutting concern, and it contains the pointcut specification, introductions, advices and methods. The aspect makes the actual changes to the program execution in such way that on the needed places, which are defined in the pointcuts, injects the changed code which is called the advice. To create a high quality aspect-oriented system, an adapted-to-AOP-approach requirements engineering is needed – a system must be looked at like a base system with extensions. Afterwards, the basic code is to be written, and later, that basic part is upgraded writing the aspect code. While creating the aspect, it is needed to correctly specify the pointcuts to assure that the aspects don’t interfere with each other because of the accidentally similarly defined pointcuts. In the thesis, the aspect-oriented approach is explained on a “Hello World!” example and on the second example which uses the “around” advice to control the execution of the program.