Avast promises pro-active protection from online threats including viruses, spyware, and rootkits while guarding traditional (Internet, disk media) and nontraditional (network and P2P/IM traffic) infection vectors.

Avast's resident shield provides real-time operating system protection and claims to be able to detect a virus before it infects a computer. Avast also has built-in measures to prevent itself from being shut down. Additionally, the program includes various scanners for e-mail and news feeds.

Avast has a light firewall built in called the network shield. It actively scans network traffic for worms and other threats.

Another notable feature is Avast's Virus Recovery Database which creates a file integrity database that can repair virus-infected files to their original state.

The free version of Avast (Home Edition) is only available for home users, not businesses. Registration is required to use the software beyond the 60-day trial period.