In the present paper, a design method of model reference adaptive controllers for processes with uncertain relative degrees r, r + 1 or r + 2 (r is an element of N), and with unknown signs of high-frequency gains, is presented. This is an extension of Morse's adaptive controllers where it was assumed that the relative degrees are uncertain but known to be 1 or 2. It is shown that single adaptive control schemes can deal with unknown signs of high-frequency gains, and enlarged uncertainties of relative degrees compared with the previous works, and that the resulting model reference adaptive control systems are asymptotically stable.