Labin idioms are one of the four groups of central Istrian subdialect of the Ekavian Ĉakavian dialect, which has been the subject of dialectological researches for a century. In this thesis, the phonological and morphological features of this group are analysed in detail as well as presented with their detailed phonological and morphological descriptions. The phonological description includes a representation of the two observed vowel and prosodic systems (specific to speeches with one- or two-accent system) and three different consonant systems with two subsystems in each of them (which differ by the presence and modifications of cakavism and the status of the phoneme /ĺ/). The morphological description comprises a display of open-class words: declension of nouns, pronouns, adjectives and numbers as well as conjugation of verbs, taking into account the morphonological issues. These analyses and their results are used to justify the linking of Labin group of idioms to a separate dialectal unit, i. e. argument their separation as a distinguished group or type of idioms. Besides the precise stratification of Ĉakavian Ekavian idioms of Labin, on the basis of all the collected data and its analysis, the paper offers the classification into systems of dialectologically lower rank – subgroups of idioms. The starting classification criterion was the accentual one (the presence of one- or two-accent system). Some other phonological and morphological criteria were added (the reflection of the back nasal vowel *ǫ, the status of the phoneme /ĺ/, the grammatical morpheme for the instrumental singular of feminine noun words, the implementation of unification at the final position of the grammatical morpheme for the 3rd person plural of the present tense of verbs). Taking into account the mentioned criteria, three subgroups were defined within the Labin group of idioms, which comprises 58 local idioms: Southern (comprising 18 local idioms with one-accent system), Northern (representing the core of this group and comprising 35 local idioms with two-accent system) and Northeastern (comprising 5 local idioms, and becoming closer to the idioms of the Northeastern Istrian Ekavian Ĉakavian subdialect which it borders in a part of its features, but the majority of them are congruous with other idioms of the Labin group). The intention of this research and the dialectological description of Labin idioms is to contribute to complementing dialectological mappings of not only the central Istrian subdialect, but also the Ekavian Ĉakavian dialect in whole, thus contributing to the Croatian Ĉakavology.