The main idea of this research was to find out if there is a relationship between students' undertakings within Craft and Technology education and their ability to understand technological concepts. Study participants' technological knowledge and reasoning was measured with a questionnaire regarding mechanical systems connected with simple physical phenomena. The research was undertaken in Finnish and Estonian schools during the years 2014-2016. The research model was quantitative survey and the data was collected using a questionnaire distributed to 303 students in Estonia and 317 in Finland. The age of study participants was eleven and thirteen. The results highlighted general lack of technological knowledge and reasoning, which could be due to old-fashioned pedagogical methods in teaching technology. The total average of right answers to 28 questions was in Estonia 15.4 and in Finland 15.0. Main difference was found between Finnish and Estonian 11-year-old students while the Estonian figure was 14.9 and 14.1 in Finland. For 13-year-old students, the difference was almost diminished while the average in Estonia was 15.8 and 15.7 in Finland. This is explained by curriculum differences. In Finnish technology education both Technical craft and Textile craft are compulsory for both boys and girls. In Estonia, students can choose the subject based on their wishes and interests. This allows students to study in greater detail the subject that they are really interested in. In addition, boys' and girls' different interests and earlier experiences obviously have an impact on motivation for learning about technology.