This paper contains data from an investigation of the potential use of natural materials like coconut fibres as reinforcement in tropical soils, A silty soil was used as the fill for laboratory tests and model retaining walls to represent the engineering properties of tropical soils (particularly those from Bangladesh). The shearing interaction between soil and coconut ropes was determined by small direct shear box tests. Samples of rope were left buried in soil to assess their durability The rope made from coconut fibre interacted very well with soil so that the surface shearing resistance was equivalent to soil-on-soil sliding. Model retaining walls were constructed using coconut ropes as reinforcement within soil and the walls were surcharged to failure. The ropes enhanced the strength of the soil block very significantly and there was good argument between the actual surcharge to cause failure and that predicted by simple analysis using the laboratory-determined shear strength parameters.