U radu je predstavljena nedestruktivna procjena koncentracije fotosintetskih pigmenata (ukupnih klorofila i karotenoida) u lišću hrasta lužnjaka pomoću prijenosnog optičkog klorofilmetra CCM-200. Istraživanje je provedeno 2015. godine na biljnom materijalu izloženom različitim tretmanima vlažnosti tla. U kontrolnom tertmanu sadržaj vlage u tlu održavan je iznad poljskog vodnog kapaciteta, dok je u sušnom tretmanu biljkama voda bila uskraćena 112 dana (1. 4. – 21. 7.). U drugom dijelu vegetacijskog razdoblja (22. 7. – 22. 10.) u oba tretmana vlaga tla održavana je iznad poljskog vodnog kapaciteta. Na temelju lišća uzorkovanoga istovremeno u oba tretmana i to sredinom jeseni (27. 10.) izrađene su kalibracijske jednadžbe koje opisuju odnos indeksa relativnog sadržaja klorofila izmjerenoga pomoću klorofilmetra i stvarne koncentracije fotosintetskih pigmenata (utvrđene laboratorijski) pred sam kraj vegetacijskog razdoblja. Jednadžbe su konstruirane posebno za kontrolni, a posebno za sušni tretman. S obzirom na takav dizajn pokusa i vrijeme uzorkovanja, primarni cilj rada bio je ispitati utjecaj dugotrajnog sušnog razdoblja na homogenost parametara kalibracijskih jednadžbi (Y-odsječaka i nagiba pravaca). Na temelju dobivenih rezultata zaključeno je da parametri kalibracijskih jednadžbi nisu bili utjecani sušnim tretmanom. Prema tome, rezultati istraživanja ukazuju na to da klorofilmetar CCM-200, uz primjenu odgovarjućih kalibracijskih jednadžbi, predstavlja pouzdan alat za nedestruktivnu procjenu koncentracije ukupnih klorofila i karotenoida u lišću hrasta lužnjaka, bez obzira na različite režime vlažnosti tla kojima je biljni materijal bio izložen tijekom vegetacijskog razdoblja. Uz to, u radu je utvrđeno da bi preciznost procjene stvarne koncentracije fotosintetskih pigmenata bilo moguće i dodatno poboljšati korekcijom klorofilnog indeksa sa specifičnom lisnom masom. The concentration of photosynthetic pigments (chlorophylls and carotenoids) in leaves of forest trees is a good indicator of the photosynthetic efficiency, level of nutrition with nitrogen and autumn leaf senescence. Thus the photosynthetic pigment concentrations is one of the most significant parameters related to the physiological status of plant. Change in pigment concentrations of leaves indicate presence of environmental stress. Well-timed detection of environmental stress play a crucial role in preventing damage on seedlings and saplings in forest nurseries and wood mass production in forest cultures and plantations. Traditional methods for determining the concentrations of photosynthetic pigments represent an obstacle to continuous monitoring concentrations of photosynthetic pigment in leaves of forest trees, primarily because they are relatively expensive, long lasting and require destruction of plant material. However, portable optical chlorophyll meters such as CCM-200 (Opti-Sciences, Tyngsboro, Massachusetts, USA) and SPAD-502 (Minolta Camera Co., Osaka, Japan) is a reliable alternative to traditional laboratory methods. To use chlorophyll meters as a tool for estimating photosynthetic pigment concentrations in leaves, it is necessary to construct regression equations (calibration equations) that reliably describe the relationships between the relative index of the total chlorophyll content in leaves (CCI) and the total pigment concentrations in leaves, determined by standard laboratory methods. In the present study, we set up experiment to establish the ability of the hand-held CCM-200 chlorophyll meter to accurately estimate the content of the photosynthetic pigments in leaves of Quercus robur L. with contrast level of soil moisture. The objectives of the present work were: (i) determine whether the long-lasting drought period significantly influences the relationship between the CCI obtined by CCM-200 and the concentration of photosynthetic pigments (total chlorophyll and carotenoid); (ii) construct calibration equations for non-destructive estimation of photosynthetic pigments in Q. robur leaves; (iii) to analyse the improvement estimation of photosynthetic pigments concentration when CCI was corrected with specific leaf mass. The research was carried out during the year 2015 on 60 two-years old plants grown in the greenhouse located in the Croatian Forestry Institute Jastrebarsko. Plant material was grown in 50 liter containers previously filled with soil originating from a natural oak stand. In the spring of the 2015, at the beginning of the study the mean height of investigated plants was 23.9 ± 4.8 cm. During the study, plant material was exposure to different level of soil moisture. In control treatment soil water content was kept above field capacity, while in drought treatment plants were exposed to water reduction during 112 days (1st of April – 21st of July). In second part of growing season (22nd of July – 22nd of October) in both treatments soil water content was kept above field capacity (Figure 1). Calibration equations, that describe relationship between relative chlorophyll content index measured with chlorophyll meter and actual photosynthetic pigment concentrations in sampled leaves (laboratory determined) at the end of growing season (27th of October), were constructed for both treatments (Table 2 and 3; Figure 4 and 5). Obtined results show that parameters of calibration equations were not affected by drought treatment (Table 4). Therefore, when using appropriate calibration equations, clorophyll meter CCM-200 can be considered as reliable tool for non-destructive estimation of total chlorophylls and carotenoids in Q. robur leaves, regardless of different soil water regimes during the growing season. Additionaly, this research confirmed that it is possible to improve the estimation of actual photosynthetic pigment concentration by using chlorophyll content index corrected with specific leaf mass (Table 2 and 3; Figure 4 and 5).