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Natural collapsible soils in Brazil are generally found in aluvial, colluvial and residual soils that have suffered lixiviation in the superficial horizons, in regions where dry and wet seasons are clearly marked, and in arid or semi-arid regions with very low soil water content. There are known occurrences of collapsible soils in the States of Amazonas, Piaui, Ceara, Pernambuco, Bahia, Minas Gerais, Tocantins, Sao Paulo, Parana, Santa Catarina, Rio Grande do Sul and the Federal District. In the last three decades, many public projects have been developed in areas where the occurrence of collapsible soil has been associated to geotechnical problems. This paper studies a collapsible soil in the State of Pernambuco; it is associated with large engineering projects such as housing. The geotechnical investigation program included test with a field apparatus, called - colapsometer, which allows the measurement of the field settlements of a small 0.08 m of diameter plate inserted at any depth inside auger holes, static and dynamic tests with penetrometer and reconnaissance borings with SPT (standard penetration test), investigation pits with undisturbed block sampling and disturbed samples for laboratory tests were also made in order to assess the type and characteristics of the soil. Laboratory work included double and simple oedometer tests with a controlled rate of water inflow of 1.0 mL/s. The soil is truly collapsible and potential collapse values increase with stress up to 160 kPa and decreases for higher values peaking behavior. The collapse values obtained with the Expanso-colapsometer are lower than those obtained in the laboratory and the collapse occurs more rapidly in the laboratory than in the field. The penetrometer DPL and Static are promising research techniques to assess the loss of a sandy soil resistance due to wetting.