In Van cats, changes in serum mineral (Na-Sodium, K-Potassium, Ca-Calcium, P-Phosphorus, Mg-Magnesium, Cl-Chlorine and Fe-Iron) and metabolite concentrations (TG-Triglycerides, COL-Cholesterol, T.Prot.-Total protein and ALP-Alkaline phosphatase) were investigated before, during and after the pregnancy. A total of 22 mature cats (19 queens and 3 fertility-proven tomcats) were used as material. Thereafter, 13 queens showed oestrus while others (n=6) did not. Samples of venous blood were collected from anoestrous and oestrous queens upon hand-mating, on the 54th day. After parturition (n=7), the number of live kittens was recorded and additional samples were collected on the 5th, 12th and 19th days of lactation. Results were also considered for small (n=3) and large number (n=4) of suckling kittens (<= 4 or >4 litters, resp.). For minerals, there was a significant (P<0.01) fluctuation in K levels during the prolonged lactation with large number of suckling kittens. However, significant (P<0.05) decrease was found for P value as the lactation period prolonged. Meanwhile, for metabolites, TG levels in previously-mated queens (becoming pregnant or not) were significantly (P<0.01) higher than those both in anoestrus and in lactation. Also, COL levels in pregnant queens were significantly (P<0.05) higher than those in all other occasions and further that there were significant decreases in COL levels both in the first and the second weeks of lactation. Collectively, present findings suggest that; a) the concentrations of K and P minerals and metabolites studied per se (TG, COL, T.Prot. and ALP) changed markedly during the late pregnancy and prolonged lactation, and b) declines in minerals (P) and metabolites (COL) become even greater when the number of suckling kittens increased in queen Van cats during breeding season.