The paper analyses the factors which influence minimal features of detected adjacent defects during the use of traditional die-to-database method of inspection of reticles and also during the use of new Parametric Models of Pattern Features Comparison method (PMoPFC method). The analysis of influence of a set of factors, describing an instrumental error of the automatic reticle inspection system, and of a set of factors, describing a reticle patterning process, on various types of adjacent defects is made. Some relations are given, describing interrelation of the size of the minimal adjacent defect and the pixel size of the automatic reticle inspection system. A concept of the optimum and preset sizes of the minimal detected defect is introduced. The analysis of dependence of the number of false defects on the size of the preset minimal detected adjacent defect is made, as well as a criterion to choose an optimum capability of detection of adjacent defects is given. In conclusion, parameters of automatic reticle inspection systems developed at "KBTEM-OMO" of Planar Concern are given, specifying the adjacent defects detection capability. Also the parameters of the systems designed for 0.35 μm, 0.18 μm and 65 nm processes are described.