Background Guidelines recommend liver biopsy to rule out significant inflammatory activity in chronic hepatitis B (CHB) patients with elevated hepatitis B virus (HBV) DNA but without other indications for treatment. Aim To study rates and determinants of clinically significant liver inflammation. Methods We selected patients with HBV DNA > 2000 IU/mL from the SONIC-B database. The presence of significant inflammation (METAVIR >= A2 or HAI >= 9) was assessed by liver biopsy and correlated with alanine aminotransferase (ALT) levels (according to AASLD upper limits of normal [ULN]) and stratified by the presence of significant liver fibrosis (Ishak >= 3 or METAVIR >= F2). Results The cohort included 2991 patients; 1672 were HBeAg-positive. ALT was < ULN in 270 (9%), 1-2 times ULN in 852 (29%) and > 2 times ULN in 1869 (63%). Significant fibrosis was found in 1419 (47%) and significant inflammatory activity in 630 (21%). Significant inflammatory activity was found in 34% of patients with liver fibrosis, compared to 9.5% of those without (P < 0.001). Among patients without fibrosis, significant inflammatory activity was detected in 3.6% of those with normal ALT, 5.0% of those with ALT 1-2 times ULN and in 13% of those with ALT > 2 times ULN (P < 0.001). ALT Among patients without significant fibrosis, an ALT level < 2 times ULN is associated with < 5% probability of significant inflammatory activity. If fibrosis can be ruled out using non-invasive methods, liver biopsy solely to assess inflammatory activity should be discouraged.