Text-password based authentication schemes are a popular means of authenticating users in computer systems. Standard security practices that were intended to make passwords more difficult to crack, such as requiring users to have passwords that "look random" (high entropy), have made password systems less usable and paradoxically, less secure. In this work, we address the need for enhancing the usability of existing text-password systems without necessitating any modifications to the existing password authentication infrastructure. We propose, develop and evaluate a system that automatically generates memorable mnemonics for a given password based on a text-corpus. Initial experimental results suggest that automatic mnemonic generation is a promising technique for making text-password systems more usable. Our system was able to generate mnemonics for 80.5% of six-character passwords and 62.7% of sevencharacter passwords containing lower-case characters (az), even when the text-corpus size is extremely small (1000 sentences).