Poly(amidoamine)s dendrimers (PAMAM)s of different generations (Gn, where n = 1–3) were prepared via Michael addition/amidation reactions following a well-established procedure and their molecular weights were determined using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF). The existence of amine functional groups on the molecules periphery was proved with proton nuclear magnetic resonance (1H NMR) whereas the main features of such polymers were additionally evidenced with 13C NMR. The polymers were included as modifiers during the synthesis steps of melamine-urea-formaldehyde (MUF) resins for the purpose of probable enhancement of some properties. The contact angle measurements of the modified resins indicated better wetting over wood substrates while their active participation in the condensation and crosslinking reactions with wood substrates was ensured with thermomechanical analysis (TMA). The positive impact on the modulus of elasticity (MOE) of the corresponding particleboards can be attributed to their ability to impart sufficient flexibility to the resulting network structure after effective incorporation via chemical bonds. This effect, led to improvement of the particleboards strength and resistance to swelling after immersion in boiling water for 2 h. This improvement occurred for a wide range of MUF resins prepared: (i) with different formaldehyde:(M + U) ratios; (ii) in some cases with more urea charged as a substitute of the expensive melamine at a fixed formaldehyde ratio. This is considered to be an advantage due to (i) lower toxicity for the lower proportion of formaldehyde used. (ii) Economically, as less of the expensive melamine is added without affecting the performance of particleboards manufactured with these resins even upon exposure to hydrolytic conditions.