The study covers development and importance of mobile (cellular) telecommunication services, which developed during last about 25 years and are currently the most important and profitable telecommunication sector. The development of mobile telecommunications becomes essential factor of economic growth in many countries, especially in developing countries. Currently due to the scientific and technological progress as well as the implementation of the LTE system and new mobile 5G system, cellular telecommunication becomes the basic element of the modern broadband telecommunication infrastructure and internet services. Growing importance of the mobile telecommunications is also connected with great popularity of new mobile terminals - smartphones and tablets. These terminals together with the technology known as cloud computing changed also the ICT market. The study relates to the situation in many countries, but mainly to Poland.