Changes in society, intensive expansion and variety of technologies require new quality of teaching and learning. This quality may be brought about education technology based on modern informative technique means (Schacter, 1999). Using ICT in educating stimulates changes in curricular, develops learning environments, leads to a better quality of learning, professional development, makes impact on education system, school management and changes of school culture (Haefner, 1998, Coughlin, 1999, Schacter, 1999, Markauskaite, 2001, Juceviciene, Otas, and Telšius, 2002). The implementation of ICT in secondary schools have been analyzed by Branson (1990, Harwey (1990), Petrauskas (1990, 1998), Achtenhagen (1995), Dwyer (1996), Gibson (2001), McCormick Scrimshaw (2001), Otas (2001), Juceviciene (2002), Chreptaviciene, Kondratas (2003), Petkunas (2003), Brazdeikis (2003) and others. However, in the above works attention is focused on the elements of some activities by teachers and students, perturbations of ICT implementation, ICT implementation influence on changes of education system, ICT competence of teacher and other. There is no established system of criterions and indicators, which empower to diagnose the present situation of ICT implementation in secondary schools in different stages; it is difficult to establish a whole view, to establish the problems of ICT implementation, the ways of possible problems solving and project further steps for ICT implementation. Therefore in this article is solving the scientific problem: - what may be characteristic, criterions and indicators reflecting the different ICT implementation stages? The objective of this article is to present and validate the criteria and indicators of ICT implementation stages in secondary school. The article analyses 4 stages of ICT implementation (Anderson and Weert, 2003 Juceviciene, 2003, Niemi and Karlajainen, 2000): 1) emerging - initial stage, during which the schools are supplied by computers and software, community tries to reach the computer literacy; 2) applying - ICT is inserted into traditional educational and management processes, teachers begin to use ICT in different disciplines. However, in essence, this is a learning stage how to use ICT for one's needs; 3) infusing -ICT is inserted and integrated into the curricular of all subjects; this is a stage of understanding when and how to use ICT in teaching; 4) transforming - the essence of this stage is the ability of the school to self-evaluate like organization and creative it renovate by using ICT. The essential transformation of pedagogical system is running in this stage. A new learning and empowering emerges. The pedagogical system is shifted towards a student. Some characteristics, criteria and indicators, associated with ICT facilities, achievements of students and teachers, significant events of school community of ICT using where adopted for the research. A questionnaire on criteria and indicators of ICT implementation stages establishment were presented for schools' evaluation. The research involved 54 schools in one municipality. The questionnaire was distributed by e-mail. Obtained answers were processed using package of SPSS software. The results of research allowed further correction and development of criterions and indicators.