Observations are based on original research. A background information is given about plant parasitic nematodes and the observations made on the infected root of apple tree are reported. A total of 220 samples of apple tree roots of 10 different localities of Kalat district, Balochistan, were collected. Apple roots were found infected with nematodes belonging to the genera, Aphelenchus, Boleodorus, Helicotylenchus, Merlinius, Pratylenchus, Psilenchus and root knot nematode Meloidogyne. Root tissue damage caused by root knot nematode was studied and repoted. Study of histology sections revealed enlargement of cells of cortical region, distortion of cells with broken boundaries and giant cell formation. Numerous cells had sections of eggs masses, larvae and female in them. This information is useful for students, teachers and research workers in field of plant pathology, plant nematology as well as to the farmers and apple plantation growers.