Following the definition of the task of the anti-spoofing systems to discriminate between real accesses and spoofing attacks, anti-spoofing can be regarded as a binary classification problem. The spoofing databases and the evaluation methodologies for anti-spoofing systems most often comply to the standards for binary classification problems. However, the anti-spoofing systems are not destined to work stand-alone, and their main purpose is to protect a verification system from spoofing attacks. In the process of combining the decision of an anti-spoofing and a recognition system, effects on the recognition performance can be expected. Therefore, it is important to analyze the problem of anti-spoofing under the umbrella of biometric recognition systems. This brings certain requirements in the database design, as well as adapted concepts for evaluation of biometric recognition systems under spoofing attacks.