Increased serum lipoprotein a (Lpa) is an independent risk factor for atherosclerosis in renal transplant recipients (RTR). The higher level would be due to genetic factors such as apolipoprotein a [apo(a)] isoforms and/or environmental states such as prescribed drugs and diets. In this study we evaluated seventy five RTR and thirty healthy individuals as control groups (C) for apo(a) isoforms, Lpa concentration, serum triglyceride (Tg), serum cholesterol (chol), Serum creatinine (Cr) and serum homocysteine (Hcy) concentration. M/F ratio was 30/45 with the mean age 30+7 years and duration of transplantation 57+10 months. High molecular weight (HMW) and low molecular weight (LMW) apo(a) isoforms, i.e.> 35 and <35 kringle 4, were observed in 71% and 29% of RTR group vs. 83% and 17% of C group, respectively. The average of Lpa concentration was highly significantly different between HMW apo(a) and LMW apo(a) isoenzymes, 27.2+15 mg/dl and 76+50 mg/dl (p=0.003) in the RTR group, vs. 14.8+8 mg/dl and 24.1+9 mg/dl (p=0.03) in the C group, respectively. Lpa and chol concentrations did not correlate with each others and also were not higher in the eight RTR with Cr more than1.8 mg/dl. The absolute levels in the malfunction RTR also, were not different in the various apo(a) phenotypes. But interestingly, Hcy level was higher in HMW apo(a) than LMW apo(a) isoenzymes (19.6+13 vs. 10+4 micromol/L, p=0.003). A relationship also, between Lpa and Tg, but not chol was observed. The higher Tg was associated with HMW (153+37 mg/dl) than LMW (166+67 mg/dl) isoforms of apo(a) (p=0.027). In conclusion Lpa concentration is higher in LMW isoforms of apo(a), but Tg and Hcy concentration is higher in the HMW isoforms of apo(a).This would be used as a guideline to select the most appropriate drug for different apo(a) isoforms.