The aim of this paper is to give the overview and analysis of English nominalizations ending in suffixes -hood and -ness within the framework of cognitive linguistics. Cognitive approaches to word formation treat the meaning of affixes as a category with a prototype and its extensions. We have assumed that cognitive processes of metaphors and metonymies are responsible for the extensions. Our corpus consists of examples that display the central meaning (the state or quality of being A/ N) and of those showing other senses. For the suffix -hood these are: a group of people sharing the thing referred to by N; a period of time during which one is N; an instance of the quality referred to by the adjectival base; an area of the thing referred to by N; a part of the body and an action of making something A. These meanings are metonymically and metaphorically derived. DEFINING STATE OR PROPERTY OF ONE MEMBER FOR THE WHOLE CATEGORY (GROUP) metonymy creates the 'group' meaning; from this metonymy the activation of PEOPLE LIVING IN A PARTICULAR PLACE FOR PLACE metonymy produces 'area' meaning; the sense 'period of time' can be explained via THE STATE OF BEING N FOR THE PERIOD OF TIME DURING WHICH ONE IS N; the meaning of 'part of the body' is enabled by STATE OF THE WHOLE PERSON FOR PART OF THE BODY; STATE FOR ACTION metonymy is found in the example where we percieve state as an action in which one makes use of that state. This metonymy produces ACTION FOR RESULT metonymy which creates the meaning of 'an instance or example of being A'. A great number of nominalizations ending in -ness have the meaning of an instance or example of the quality or state denoted by the adjectival root. Within this meaning the following metonymies and metaphors create the following meanings: STATE OR QUALITY FOR EVENT DEMONSTRATING THAT STATE OR QUALITY metonymy produces the meaning of an act of being A; EFFECT FOR CAUSE metonymy enables us to see certain state as a cause of that state (an event, a person or a situation that brings about A + ness); GENERIC FOR SPECIFIC metonymy allows nominalizations to be used with the indefinite article and become pluralized when they denote 'a manifestation or an instance of a state in a certain time period' or 'a specific type of A + ness'; STATE FOR OBJECT EXEMPLIFYING THE STATE metonymy can even produce the meanings that can be characterized as physical objects. The suffix -ness can have 'action' reading via STATE FOR ACTION and 'a period of time' meaning via STATE OF BEING A FOR THE PERIOD OF TIME DURING WHICH ONE IS A. Metaphor STATES ARE LOCATIONS creates locative meaning of some -ness nominalizations. Finally, similar to the suffix -hood, -ness can also denote 'a collectivity', to be more precise, 'a group of animals', via DEFINING QUALITY OF ONE MEMBER FOR THE WHOLE CATEGORY OF MEMBERS WITH THE SAME QUALITY metonymy. The mentioned metonymies and metaphors operate posterior to suffixation and can serve to show that the richness of suffixal meanings is not random, but highly motivated. This paper can be used as a study of other affixes within cognitive linguistics paradigm. The better understanding of connection between word formation processes and cognitive operations such as metaphors and metonymies is also possible.