Description: Present paper aims to investigate the phenomenon of the private tutoring (PT) in Croatian secondary education. PT is defined as an additional tuition in school subjects that is being paid for. Secondary school teachers, students, university lecturers or other professionals in Croatia provide tuition both to individuals or groups. The scope, nature and effects of PT have been examined on a sample of 510 secondary education pupils. In addition, a set of qualitative methods have been applied to investigate phenomenon in depth from the perspective of the providers of PT services and Ministry of Education of Croatia. The aim of the present research is to determine the scope and nature of the phenomenon in Croatia as well as to depict the characteristics and reasons of the typical user of the services. By including the other sides of the PT phenomenon (providers and regulators) present study aims to give an in depth picture of the complexity of the PT. Methodology: The sample covered only pupils from general secondary schools - gymnasiums, located in the capital city (Zagreb) and surrounding area (County of Zagreb) - attending 3rd grade (grade before last) in year 2004/2005. Stratified random selection of the schools was used. Stratification was based on the location of the school, and at the first level there were two stratums: Zagreb and the County of Zagreb. At the second level, the stratum of Zagreb was divided further into a) central city schools and b) schools on the outskirts. Within each stratum, schools were randomly selected. Out of 20 "gymnasiums" in Zagreb, 10 were selected (7 central city + 3 outskirts), and 2 were selected out of 8 in the County of Zagreb. Within each school, participants were selected randomly, using the systematic sampling. The number of participants to be surveyed in each school was proportionate to the total number of third grade pupils in the school within the stratum. A total number of 510 pupils participated in this part of the research. The international questionnaire was applied. The used questionnaire was developed by the international group of researchers (authors included) on several occasions during last three years. The questionnaire has proved to have sufficient metric characteristics and has showed reasonable ecological validity. With the aim of getting an insight on the position and opinion of the Ministry of Science, Education and Sports about the phenomenon of private tutoring we interviewed the State Secretary for Secondary Education. The interview was carried out in line with predefined protocols for discussion. We explored what is the current policy of the Ministry or what policy Ministry intends to implement in regard to private tutoring, as well the State's Secretary's opinion on the scope of private tutoring in Croatian education, and his beliefs on the effects of this phenomenon on pupils, teachers and educational system as a whole. At the same time we also interviewed three private tutors - two teachers and one student. These mini cases were there in order to include a voice "from the other side", the provider of services and serve as an illustration of the position of private tutors and their opinion on the scope, cause and effects of private tuition. Interviews were conducted in line with the predefined protocols for discussion. Conclusions: The presented results unambiguously indicate the existence of the private tutoring phenomenon in the context of Croatian society and its educational system. Furthermore, the scope of private tutoring and its omnipresence in different educational phases and various subjects may serve as confirmation of the hypothesis that PT represents a problem of the Croatian educational system that needs close monitoring and adequate intervention. The Ministry of Science, Education and Sports does not recognise this phenomenon in its legislature and does not monitor the demand and supply forces on the PT market. This situation of ignoring the phenomenon presents very fertile ground for the development, establishment and growth of PT. The results show that 54.5% of pupils in the second year of secondary education take private lessons in at least one subject. This high percentage of students in private tutoring during secondary schooling points to many problems related to the efficacy of the educational system, the quality of teaching in schools, the adequacy of the assessment system and the overall burden placed on pupils. Results unambiguously show that mathematics is the subject in which most of the pupils seek additional help. 89% of students and 87 % of secondary school pupils using private lessons report mathematics as the subject in which they took PT which is followed by physics (46%), chemistry (16%) and foreign language (11%) in secondary school sample. Most of the respondents in the survey report that they have taken PT lessons from just one subject. Indicators that over 40% of all secondary school pupils has taken or are taking PT lessons in Mathematics suggest that Ministry needs to pay special attention to the subject curriculum of Mathematics as present subject curriculum seems to be inadequate for most users.