MANOVA is a variant of ANOVA that is applied when one wishes to analyse several dependent variables at the same time. These dependent variables should be conceptuallyrelated to the hypothesis and each other. They need to be score rather than categorical variables.
Essentially MANOVA computes a composite variable based on the several dependent variables and then tests to see whether the means of the groups on the combined dependent variables differ significantly.
MANOVA helps deal with the problems created by multiple significance tests being applied to the same data.
Please refer to Chapter 23, pages 212-220, Howitt, D. and Cramer, D.(2008). Introduction to SPSS. Pearson.