This study is being conducted to compare the safety and effectiveness of switching treatment from lamivudine to telbivudine (LdT) against continued lamivudine treatment. Results from patients who were taking lamivudine and then switched to telbivudine will be compared with the results from patients who continued on lamivudine alone.

Inclusion Criteria:

• Documented clinical history compatible with chronic hepatitis B
• Patient has compensated liver disease
• Patient has received previous treatment with lamivudine for a duration of at least 3 months and not more than 12 months

Other protocol-defined inclusion criteria may apply.

Exclusion Criteria:

• Patient is pregnant or breastfeeding
• Patient is co-infected with hepatitis C, hepatitis D or HIV
• Patient previously received antiviral treatment for hepatitis B other than lamivudine in the preceding 12 months

Other protocol-defined exclusion criteria may apply.