Iconography, which is formed by combining two Greek lexemes eikon + grahein, is a branch of studying the history of art that turns to surveying, concept recognition, and description of signs present in the artwork. This branch with a historical root drew much attention during the 20^th century and more accurate and scientific studies were performed about it. Since the western art, especially during the Middle Ages and Renaissance, was under influence of Christianity, artists utilized a lot of signs and symbols to mentioned to stories and Christian figures. Several researchers were encouraged to present more adequately defined method to study iconography. In this line, Erwin Panofsky (1892- 1968), relying on hypothesis proposed by Aby Warburg (1866- 1929) which now a day is known as the spiritual father of the Iconography. Both German art historians, suggested the topic of iconology, forming by combination of eikon + logos. The name of Iconology (Italian: Iconologia), is derived of the fundamental volume by Cesare Ripa (1560? -1622), Iconologia overo Descrittione Dell'imagini Universali extracted from Antiquity and other places, published in 1593 in Rome by the heirs of Giovanni Gigliotti.  In this theory, each artwork is studied and reviewed by the cultural and historical values of its own creation era. The values on which the beliefs of a nation are based. In order to access to the hidden meanings in deep layers of artworks, Erwin Panofsky proposed three phases: his plan started with a pre-iconography that includes visual patterns of a work and its identification information; the second phase is analysis of iconography turning to introducing the theme of the work, story(s) and figures displayed in it. This analysis is the cognition that the audiences obtain about the certain concepts conveyed through religious, artistic sources or oral traditions. The third phase is the interpretation of iconology which is in relation with symbolic values concealed in the work. In iconology topic, the cultural, historical circumstance present in artistic atmosphere of the artwork creation period is surveyed. Regarding this attitude toward art criticism, it can be claimed that these three phases, along with each other, form the most perfect type of criticism in which all the dimensions of an artwork is taken into consideration and thus, iconology needs the highest level of critic knowledge. Since in Italian art in Medieval and Renaissance, several symbols are used to convey various religious concepts; it is one of the best present art for criticism in both sections of iconography and iconology. Using descriptive-comparative research method and based on library and written sources, this article studies the differences between these two categories and use them in Renaissance art with a case study of the well-known work of Piero della Francesca, The Brera Madonna (also known as the Pala di Brera, the Montefeltro Altarpiece or Brera Altarpiece). This is a painting executed in 1472-1474, by the technic tempera on panel, in 248 cm × 150 cm, entitled as the most famous work of the 15^th century for this legend. This work which is now kept in Brera Gallery in Milan displays of the legends of holy book, which was commissioned by Federico III da Montefeltro (1422-1482), the Duke of Urbino - a walled city in the Marche region of Italy, south-west of Pesaro, a World Heritage Site - from 1474, the figures presented in this work were unknown for a long time; after transferring it from Urbino to Milan in 1811, following the Napoleonic requisitions, followed by extended studies, they were identified. The work represents a sacred conversation, with the Virgin enthroned and the sleeping Child in the middle, surrounded by a host of angels and six saints. This masterpiece represents a sacred conversation, with the Virgin enthroned and the sleeping Child in the middle, surrounded by a host of angels and saints. The Brera altarpiece is an example of the perspective research carried out by the artists of central Italy in the second half of the fifteenth century. It is a monumental work, with a magnificent treatment of light, immobile and an iconographic repertoire of extraordinary richness. Della Francesca’s work is the first Sacred Conversation developed mainly vertically: numerous altar tables throughout central-northern Italy are inspired by it. Surveying it as a case study can be a suitable example for practical use of these two iconography and iconology for art critics.