The genitive singular ending is -n.
Examples:
Note: If a proper name ends with a consonant add a vowel -i before the ending:
Personal pronouns genitive forms are:

The use of the genitive form

The genitive form is used in Finnish to express e.g. ownership and possession.

The genitive is used as an attribute

        Italian pääkaupunki
        the capital city of Italy
        Helsingin yliopisto
        University of Helsinki
Notice, that a genitive attribute is always in genitive form regardless the main word's form:
Minä opiskelen Helsingin yliopistossa. I study at the University of Helsinki.
Minä asun Helsingin keskustassa, I live in the center of Helsinki.

Special use of the genitive case occures with täytyy must.

The subject is marked with the -n and the verb täytyy is in the same form regardless of the person.

The genitive form is used together with postpositions

Genitive (–n form) is often used together with postpositions such as kanssa ‘with’, edessä ‘in front of’, takana ‘behind’ etc. Genitive + kanssa describes association between words and genitive + edessä, takana etc. indicates location. Indo-European languages use mainly prepositions but Finnish favors postpositions comp. with a friend ystävän kanssa, under the chair tuolin alla.