We studied the long-term outcome of children with mild acute post streptococcal glomerulonephritis (APSGN) APSGN hospitalized at St. Al Zahra hospital, Isfahan, Iran from 1993-1998. The patients were subdivided into two groups according to the duration of follow-up. Group A consisted of 15 patients and group B consisted of 12 patients, followed up for 4 and 8 years, respectively. The male to female ratio was 1.45/1. The mean GFR in group A and B was 127.7 +/- 26 mL/min/1.73 m2 and 128.57 +/- 7 mL/min/1.73 m2, respectively. There was no statistically significant difference between GFRs in two groups. Comparing the mean systolic blood pressure in two groups did not demonstrate a significant difference; 95.33 +/- 7.1 mmHg in group A and 102.5 +/- 14.06 mmHg in group B. However the mean diastolic blood pressure in group B was significantly higher than group A; 65.4 +/- 11.71 mmHg vs 61.33 +/- 3.51 mmHg. Our study found that even mild APSGN may lead to some degree of renal impairment, and rising diastolic blood pressure maybe an early clinical sign of renal impairment in APSGN.