Multivariate data analysis (MVDA), a new statistical approach in terms of landfill research, was performed at the evaluation of data sets from three investigations. The interrelationships among variables as well as variation between observations could be examined. Causal relations between experimental factors and response variables have been identified using scatterpott interpretation. The ease of using MVDA at data evaluation is proved. MVDA techniques as follows were applied: principal component analysis (PCA), partial least squares modelling (PLS) and partial least squares discriminant analysis (PLS-DA).