This article presents an approximation of evasion; it seeks to define the concept of tax evasion taking as an economic approximation reference done until now. Initially, various concepts are exposed; then general causes and effects of evasion are included, also, the results of the applications of some measurement models worldwide are presented and, finally, the evasion in national taxes is estimated such as Income Tax and Added Value Tax (IVA) for Colombia between 2001-2009, such estimations are made with an econometric model and the methodology used consists in cointegration analysis, such modeling concluded that, evasion was reduced from 46.3% to 31.4% of the total collection of Income Tax and I.V.A. during the period established.En este artículo se realiza una aproximación al tema de la evasión, se busca definir el concepto de evasión tributaria tomando como referencia aproximaciones económicas que hasta la fecha se han realizado. Inicialmente se exponen los diferentes conceptos; posteriormente se incluyen las causas y los efectos de la evasión a nivel general, luego se presentan los aportes resultado de las aplicaciones de algunos modelos de medición a nivel mundial y, por último se genera la estimación de la evasión en los impuestos nacionales como lo son el Impuesto de Renta y el Impuesto al Valor Agregado IVA para Colombia en los años comprendidos entre el 2001 y el 2009, dichas estimaciones se realizan a partir de un modelo econométrico y la metodología utilizada consiste en el análisis de co-integración, dicha modelación concluyó que la evasión se redujo de 46.3% al 31.4% del recaudo total de los impuestos de Renta e I.V.A en el período de estudioThis article presents an approximation of evasion; it seeks to define the concept of tax evasion taking as an economic approximation reference done until now. Initially, various concepts are exposed; then general causes and effects of evasion are included, also, the results of the applications of some measurement models worldwide are presented and, finally, the evasion in national taxes is estimated such as Income Tax and Added Value Tax (IVA) for Colombia between 2001-2009, such estimations are made with an econometric model and the methodology used consists in cointegration analysis, such modeling concluded that, evasion was reduced from 46.3% to 31.4% of the total collection of Income Tax and I.V.A. during the period established.