This paper searches for an optimal combination of non-survey methods when constructing a Spanish interregional input-output table for the region of Madrid and the five provinces of the region of Castilla-La Mancha (CLM), given thirteen Spanish regional input-output (IO) tables for the period between 1999 and 2005. Hence, we develop different regression analyses to obtain the trade submatrices of the table. These regression analyses are based on statistical data on the road transport of goods, on input-output interpolation and extrapolation techniques to calculate the necessary coefficients. Finally a procedure is devised to tally the summation of the provincial and rest of Spain IO submatrices with the National IO table.