The present invention provides an absorbing-layer-forming composition including a blocked isocyanate such that the amount of the blocked isocyanate is 50% by mass to 100% by mass of the solid content of the absorbing-layer-forming composition and an absorbing substrate, a printed item, and a conductive pattern that are formed using the absorbing-layer-forming composition. The absorbing-layer-forming composition according to the present invention can be used for forming an absorbing layer which is capable of carrying a fluid such as an ink therein and which enables good adhesion between various types of supports and a conductive layer to be achieved. In particular, using a blocked isocyanate having a number-average molecular weight of 1,000 to 5,000 further increases the adhesion between various types of supports and the conductive layer.