In a retrospective study, the results of parasitological examinations of faecal samples from 8,560 cats and 24,677 dogs between January 2003 and December 2010 in Germany were analysed. 30.4 % of the examined dogs and 22.8 % of the cats were infected with endoparasites. The examination of the faecal samples from dogs revealed stages of Giardia spp. (18.6 %), Toxocara canis (6.1 %), Toxascaris leonina (0.6 %), Ancylostomatidae (2.2 %), Trichuris vulpis (1.2 %), Capillaria spp. (1.3 %), Crenosoma vulpis (0.4 %), Angiostrongylus vasorum (0.5 %), Taeniidae (0.4 %), Dipylidiidae (< 0.1 %), Mesocestoides spp. (< 0.1 %), Isospora spp. (5.6 %), I. ohioensis-complex (3.9 %), I. canis (2.4 %), Sarcocystis spp. (2.2 %) and Hammondia heydorni/Neospora caninum (0.3 %). Dogs in the age groups up to 3 months and > 3 up to 6 months of age showed significantly higher infection rates with Giardia spp. (37.5 % and 38.2 %, respectively), Toxocara canis (12.0 % and 12.4 %, respectively), Toxascaris leonina (1.1 % and 1.6 %, respectively), Isospora spp. (23.4 % and 11.8 %, respectively), I. ohioensis-complex (15.6 % and 7.2 %, respectively) and I. canis (11.8 % and 5.2 %, respectively) compared to older dogs. In faecal samples from cats, stages of Giardia spp. (12.6 %), Toxocara cati (4.7 %), Toxascaris leonina (0.1 %), Ancylostoma tubaeforme (0.2 %), Aelurostrongylus abstrusus (0.5 %), Capillaria spp. (1.0 %), Taeniidae (0.6 %), Dipylidium caninum (< 0.1 %) Mesocestoides spp. (< 0.1 %), Isospora spp. (6.0 %), I. felis (4.4 %), I. rivolta (2.2 %), Toxoplasma gondii/Hammondia hammondi (0.8 %) and Sarcocystis spp. (0.3 %) were detected. Cats in the age groups up to 3 months and > 3 up to 6 months of age showed significantly higher infection rates with Giardia spp. (19.5 % and 24.0 %, respectively), T. cati (8.1 % and 6.9 %, respectively), Isospora spp. (12.8 % and 8.6 %, respectively), I. felis (10.0 % and 5.9%, respectively) and I. rivolta (4.6 % and 2.9%, respectively) compared to older cats.