Cryptography is required to secure the data networks communication. This study implements Twofish cryptographic algorithm using library Chilkat Encryption ActiveX Ms. Visual Basic. Twofish operate on a block of plaintext consisting of 128 bits. There are 3 steps in Twofish algorithm, the first step is divide input bit into 4 parts, the second step was performed XOR operation between bit input with a key, and the third step processing the input bits in 16 times Feistel network. To facilitate the implementation of the coding in Ms. Visual Basic we use Chilkat Encryption ActiveX. This research using agile methods with phases: plan, design, code, test, and release. Twofish algorithm implementation using Ms. Visual Basic and library Chilkat Encryption ActiveX can be used to secure the data. The data succeed to be encrypted or decrypted and irreversible. The program can be implemented to maintain the confidentiality of the data when transmitted over the Internet. The speed encryption process need 3 times longer than the decryption. Average of time in encryption process need 0,365 second, while decryption process need 0,0936 second.