This article is devoted to the results of a comprehensive study of the meaning and use of the Past Tense forms of German dialects with the subsequent allocation of the distribution of grammatical phenomena in some places of compact residence of Russian Germans in the Altai. The material of the study was the monologic texts included in the linguistic corpus of the German insular dialects in the Altai. Thebasis of the corpus is the available records stored in the library of the Dialectological Centre of the Linguistic Institute of the Altai State Pedagogical University. The article presents dialects of six villages (Kusak, Shumanovka, Kamyshi, Podsosnovo, Krasnoarmeyskoe and Elizavetgrad) which belong to three main groups common in the Altai with characteristics of Low German, West Middle German and South German dialect areas. The records made in 1998-2016 were selected for analysis; the records of 1973-78 are used for comparison. To speak about the past, six past tense forms are used in the dialects under study. Three of them (preterit, perfect and pluperfect) are used in all groups of dialects. One construction (tun+infinitive) is used only in Low German dialects; two (double perfect and double pluperfect) are used only in the dialects with characteristics of the South German dialect area. In the dialects with the features of the South German dialect area, the preterit and pluperfect are almost completely lost (only the form of the preterit indicative of the verb sein is frequently used), the double perfect and double pluperfect are preserved; the meaning of the perfekt is broadened. In the dialects with the features of the West Middle dialect area, the preterit of notional verbs is also lost (the only verbs that are used in the preterit indicative are haben, sein, werden, modal verbs, and sometimes the verbs kommen, gehen, brauchen, kriegen, geben); the meaning of the perfekt is broadened with the main form referring to actions in the past. In the dialects with the features of the Low German dialect area, the preterit is used to a greater extent; however, gradually it is giving way to analytical forms, the perfect and the pluperfect. To a large extent, it is displaced by the analytical construction with the auxiliary verb "doune" which means "to do" in the preterite and the infinitive of the main verb. This construction is widely used in modern Low German insular dialects nowadays. The loss of the pluperfect and its compensation forms of the double perfect and double pluperfect as redundant ones is the result of their loss of the past perfect meaning under the influence of the Russian language on the insular dialects.