Soil aggregation is governed by several biotic and abiotic components including land-use management. Aggregation is essential to maintain soil physical properties and facilitate biogeochemical cycling. Hyphae of arbuscular mycorrhizal fungi (AMF) are considered to be primary soil aggregators and there is a positively correlation between AMF hyphae and aggregate stability in natural systems. Recent evidence suggests that glomalin (GRSP), a glycoprotein produced by AMF hyphae which has a cementing capacity to maintain soil particles together, is mainly involved in such aggregation. However, recently controversial results together with reported shortcoming in glomalin determinat suggest to proceed with caution when studying glomalin in connection with soil aggregation. Relationships between glomalin and soil aggregates found in Chilean soils are discussed.