This paper proposes a steganographic method based on adaptive least-significant bit (LSB) approach, using pixel-value differencing (PVD) and chaotic sequences to embed high capacity messages in a secure manner. Difference values of two adjacent pixels are used to estimate the secret bits number to insert in corresponding pixels. This technique has the advantage of inserting larger secret data in edge areas compared to smooth areas in cover images. The novelty is given by the choosing in a chaotic manner of the two pixel group to be used for both insertion and extraction. In this way, the inserted message becomes secure against message recovery attacks and spread over the whole image. Concerning the image quality and message capacity of the method, the results show the same performances obtained by Yang et al.'s method.