The prognostic significance of immunophenotype and other features including sex, age, anaemia, WBC, FAB type, and PAS staining were analysed in a group of 389 children newly diagnosed as acute lymphoblastic leukemia (ALL) and treated according to the BFM 1981/1983 protocol. The CR rate was higher (82-94%) in immunophenotypic subgroups defined as 'non-B' compared with B-ALL (54%). The probability of being in CCR at the end of follow up was 0.68 (median. observation, 3 years). Using the stepwise Cox regression analysis the following independent factors predictive of duration of CCR were selected (relative risk in brackets): 1. WBC (> 25G/1:< 25G/1 = 2.0, P = 0.0008), 2. age (> 10y:2-10y = 1.3, P = 0.04), 3. CALLA positivity (neg.:posit. = 2.4, P = 0.04), 4. CALLA within B-cell progenitor ALL (pre;preB,Calla-:Calla+ = 1.7, P = 0.007). T-ALL appeared to have a worse prognosis than U-ALL and B-progenitor derived ALL but it did not retain independent prognostic significance in multivariate analysis.