This is an announcement for the paper "Pointwise products of some Banach function spaces and factorization" by Pawel Kolwicz, Karol Lesnik and Lech Maligranda. Abstract: The well-known factorization theorem of Lozanovski{\u \i} may be written in the form $L^{1}\equiv E\odot E^{\prime }$, where $\odot $ means the pointwise product of Banach ideal spaces. A natural generalization of this problem would be the question when one can factorize $F$ through $E$, i.e., when $F\equiv E\odot M(E, F) \,$, where $M(E, F) $ is the space of pointwise multipliers from $E$ to $F$. Properties of $M(E, F) $ were investigated in our earlier paper [KLM12] and here we collect and prove some properties of the construction $E\odot F$. The formulas for pointwise product of Calder\'{o}n-Lozanovski{\u \i} $E_{\varphi}$ spaces, Lorentz spaces and Marcinkiewicz spaces are proved. These results are then used to prove factorization theorems for these spaces. Finally, it is proved in Theorem 11 that under some natural assumptions, a rearrangement invariant Banach function space may be factorized through Marcinkiewicz space. Archive classification: math.FA Mathematics Subject Classification: 46E30, 46B20, 46B42, 46A45 Remarks: 43 pages Submitted from: lech.maligranda@ltu.se The paper may be downloaded from the archive by web browser from URL http://front.math.ucdavis.edu/1211.3135 or http://arXiv.org/abs/1211.3135