Soil investigation reports form basis of decision making in the choice of site and design of foundation, with a view to avoiding failures in foundations. Unfortunately, detailed tests are most often time not carried out either as a result of huge financial involvement or scarcity of good laboratory equipment. The study therefore, establishes relationships between the index properties and the strength (detailed) properties of the tropical soil in the South-east. For the purpose of the study data on the various laboratory tests of the tropical soil samples sourced from different construction sites in the South-east of Nigeria were collated. With the results of the mechanical and physical properties of the respective soil samples eight regression models were therefore formulated, which explain the relationships of the respective soil properties to one another. In order to ensure reliability of the models, tests for significance of coefficients of the respective predictive variables and fitness of the models were carried out hence; only three of them were proven adequate. These final models as (i) YCBR1 = 6.09 + 0.79G - 0.08S + 0.03M - 0.09C + 0.24 LL - 0.30PL (ii) YCBR2 = 0.42 + 0.93G + 0.05M and (iii) Y1UCS = 14.12 + 2.40CBR were finally established. By this development in tropical region of Nigeria, when test values of the index properties are obtained, CBR properties would be calculated using the first model. Having obtained the CBR value, the unconfined compressive strength (UCS) can therefore be calculated using last model. Base on this analysis it is therefore concluded that the Index properties of the soil have significant relationships with its Strength properties.