The concepts of magnetic field strength, magnetic flux density and magnetization are important fundamental conceptsin magnetism. However, these concepts are often confused by students due mostly to different notations andinterpretations. This confusion inhibits learning by students about magnetic properties of magnets and ofparamagnetic, ferromagnetic and diamagnetic materials. It is therefore very crucial to determine some students’difficulties on these specific concepts. Hence, we prepared seven multiple-choice conceptual questions in accordancewith our specific goals and administered to one hundred and sixty-nine undergraduate students (40 first year, 34second year, 43 third year, 28 fourth year and 24 fifth year) attending the Physics Education Department of BucaEducation Faculty at Dokuz Eylül University. Also we interviewed with 11 fifth grade students about their answers.Results of our study show that students have important understanding problems and confusions about related concepts.Otherwise it is stated that this situation causes learning deficiency of magnetic properties of matters.