This paper presents the methodology and main results of a longitudinal study in Greece that explored the learning and psychosocial difficulties of immigrant pupils, as compared with those of their Greek classmates. The "Teacher-Child Rating Scale" (T-CRS) and "Child Rating Scale" (CRS) were used as instruments to measure the school adjustment difficulties of the sample, according to their teachers' ratings. A total number of 3561 scales were selected, and completed in full (by teacher and pupil) for each pupil. The sample of the study consisted of 5th and 6th grade primary school pupils (10-12 years) of Greek-origin families who came from the former Soviet Union (n[subscript 1]=1100). The control group consisted of Greek classmates of the immigrant pupils (n[subscript 2]=713). Also, teacher attitudes towards the effectiveness of current educational policies in Greece for immigrant pupils, as well as the difficulties they face during the teaching process, were explored through semi-structured interviews (n[subscript 3]=165). Immigrant pupils were interviewed to gain a better picture of their attitudes towards the Greek school (n[subscript 4]=260). This paper presents some of the research findings that focus on learning and psychosocial difficulties. Finally, suggestions are offered for Greek educational policies pertaining to immigrant pupils. (Contains 4 tables and 2 notes.)