The work presented here deals with highly actual topic since application of low cost natural fibers gives perspective of improvement of thermal insulation properties of dwellings in poor Andean regions especially in rural areas. The obtained thermal conductivity values of Ichu fibers are very promising and make researched fibers applicable for thermal insulation structures. Several natu- ral fibers were characterized with the purpose of using them as a natural thermal insulation system. It has been shown that corn fibers are considerable variable in size and dimensions; however, its apparent thermal conductivity and density are close to the one observed in glass fiber. Similar values were observed for wheat fiber mats, with the only difference that the fibers dimensions are considerably uniform. A special study was conducted for Ichu fiber, which has tubular shape. This fiber was classified into two differ- ent types: coarse and fine Ichu, showing average diameters of 0.83 and 0.39 mm respectively, with the diameter data fitting to Gamma and/or Lognormal statistical distribution. The tubular shape of Ichu fibers and long length sizes have great advantages due to the possibility to modify the staking orientation obtaining very low-density mats without significant variation in apparent thermal conductivity, especially for fine Ichu. SEM micrography of Ichu fibers (stem and leaves) shows porous internal structure, which reduce the ther- mal conductivity. For randomly fiber alignment mats density can be reduced to lower values similar to those observed for glass fibers, another advantage is the length size, making it possible to construct large size mats. The obtained thermal conductivity values of Ichu fibers are very promising and make researched fibers applicable for thermal insulation structures. Ichu fibers and other natural fiber do have similar thermal conductivity and density; however, having the Ichu fibers to be quite long, when arranged in different ways this one can reduce even more its density.