Abstract: The objective of this study was to investigate the prevalence, clinical signs, haematological and post-mortem changes resulting from natural infestation with internal helminthes in stray cats. A total of 55 stray cats (4 months to 3 years) old from both sexes were investigated, 50 cats were naturally infected with internal helminthes and 5 clinically normal cats served as control. Humanely, all cats euthanatized, autopsied and examined for internal helminthes. Results indicated that the prevalence of internal helminthes was 90.9% including eight species of nematodes: Physaloptera praeputialis (78%), Toxocara cati (40%), T. leonine (30%), Ollulanus tricuspis (40%), Ancylostoma tubaeforme (30%), Ganathostoma sp. (24%), Capillaria arophilia (12%) and Dioctophyma renale (10%) and seven species of cestodes: Dipylidium caninum (64%), Taeniae taeniaeformis (52%), Joyeuxiella pasqualei (26%), Diplopylidium nolleri (24%), Spirometra mansonoides (24%), Mesocestoides variabilis (16%) and Diphlobothrium sp. (12%), beside one species of trematodes: Paragonimus killicotti (4%). Results showed that mixed infection with >2 species were more common. Clinically infected cats showed sings of emaciation, anemia, coughing, vomiting, rough hair coat, abdominal distention and diarrhea. Furthermore, hematological changes showed significant decrease in Total erythrocytes Count (TRBCs), Hemoglobin concentration (Hb) and Packed Cell Volume (PCV), moreover significant increase in Mean Corpuscular Volume (MCV) and significant decrease in Mean Corpuscular Hemoglobin Concentration (MCHC) were also encountered which reflect macrocytic hypochromic type of anemia. Platelets count (Pt) were significantly decreased. Results also detected significant increased in Total leucocytes Count (TWBCs) due to significant increase neutrophils and eosinophils. Grossly, autopsied cats showed excessive mucous in stomach, congestion and hemorrhage in intestine, hepatomegaly, spleenomegaly, dark colored feces and large number of adult worms were seen in stomach and intestine.