The diagnosis of Mycoplasma bovis mastitis (MbM) usually comes too late. Consequently the capital early symptoms are described for a probable diagnosis in order to enable prophylactic measures and to prevent ineffective expensive treatments and loss of time. Following a definite diagnosis of MbM by culture, a repeated application of the CMT milk test combined with bacteriological culture detects infected cows and they should be culled. All cows of exceptional breeding value can be treated by repeated intramammary infusions of specific antimycoplasma antibiotics with a fair chance of healing, by preference during the dryudder period.