A total of 110 participants were interviewed to investigate the effect of hand measurements and gender on mobile phone messaging satisfaction. Physical measurements of hand-size and thumbs were recorded. This study focused on mobile phone keypad design factors; namely, key size, shape, texture, space between keys, layout and keypad simplicity. Females were found to be more satisfied with the key size and space between keys, whereas males are more satisfied with key shape. Users with smaller hands and thumbs were found to be more satisfied with key size and space between keys compared to those with larger hands and thumbs. One of the recommended improvements was to have larger keys with more space between them. Results obtained can be used by mobile phone designers to design customized mobile phones, for example, mobile phones that suit users with larger hands and thumbs, especially males.