Recently, Li and Hwang proposed a biometrics-based remote user authentication scheme using smart cards [Journal of Network and Computer Applications 33 (2010) 1–5]. The scheme is based on biometrics verification, smart card and one-way hash function, and it uses the nonce rather than a synchronized clock, so it is very efficient in computational cost. Unfortunately, the scheme has some security ... [Show full abstract] weaknesses, that is to say Li and Hwang's scheme does not provide proper authentication and it cannot resist the man-in-the-middle attacks. If an attacker controls the insecure channel, she/he can easily fabricate messages to pass the user's or server's authentication. Besides, the malicious attacker can impersonate the user to cheat the server and can impersonate the server to cheat the user without knowing any secret information. This paper proposes an improved biometrics-based remote user authentication scheme that removes the aforementioned weaknesses and supports session key agreement.