Method: Twenty cooperative quadriplegic CP children ages 8-11 years, gross motor function level 4, will be enrolled for the study. Inclusion criteria will be troublesome hypertonia that will respond to treatment with Botox® (as identified by clinical assessment and neurophysiological measures). Since cooperation is crucial for the intensive therapy children with cognitive impairment (IQ<70) or severe behavioural disorders will be excluded. The children will be randomized to one of two groups a Botox group (BG) and a control group (CG). CG children will undergo a program of intensive therapy and BG children will be given Botox, as clinically required, in addition to an equivalent program of intensive therapy. Botox injection will be tailored according to the specific child. Generally injection site will include biceps and brachioradialis , while flexors of the wrist and digits will be injected according to abnormal postures during function. Maximal total dose will be 23 IU per kg. The intensive therapy will be as clinically required and the therapy program will be fully documented.