Provided is a packaging material for blood bags, the packaging material having high water vapor permeation resistance for suppressing permeation of water in an anticoagulant solution or a red cell storage solution which are contents of a blood bag out of a packaging, and having excellent transparency and stability in water vapor permeation resistance even under a high temperature and humidity environment for extended periods of time. This packaging material for blood bags is characterized by including a laminate film (I) including a base layer (Y), an inorganic deposited layer (X) formed on top of the base layer (Y), a layer (Z 1 ) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt (A) formed on top of the inorganic deposited layer (X), and a layer (Z 2 ) containing a polymer (a) of an unsaturated carboxylic acid compound polyvalent metal salt (A) and a vinyl alcohol based polymer (b) formed on top of the layer (Z 1 ), laminating at least two laminate films (I) with the layers (Z 2 ) on the inside to form a laminate film (II), and laminating a heat seal layer on top of at least either one of the base layers (Y) of the laminate film (II).
