Irinotecan (CPT-11) and topotecan (TPT) are employed for cancer treatment and camptothecin (CPT) is a potential contaminant in anti-cancer drugs based on CPT-11 or TPT. In this work, solid substrate room-temperature phosphorimetry (SSRTP) was proposed as analytical technique for the quantification of CPT-11 in anti-cancer drugs and for the determination of traces of CPT in CPT-11 and TPT based anti-cancer pharmaceutical formulations. The phosphorescence characteristics of the analytes have been studied and experimental conditions (type and amount of the heavy atom salts used to induce phosphorescence, influence of the pH of the analyte carrier solution and the amount of surface modifier) were optimized in an univariate way. For the method aiming the determination of CPT, a further optimization using a central composite design was made in order to identify the main effects and possible interactions among factors. The best conditions had been achieved using cellulose substrate containing 332 micrograms of TlNO3 (phosphorescence inducer) and analyte carrier solution containing Britton-Robinson buffer (pH 10.5). For the CPT-11, best conditions were achieved in cellulose substrates containing 577 micrograms of SDS and 662 micrograms of Pb(NO3)2 The selective determination of CPT could be performed in samples containing a higher amount of TPT (40 times) if the signal measurement is made at the isodifferential wavelength (367 nm) of the second derivative excitation spectra. For samples containing CPT-11, selective determination of CPT could be made in samples containing CPT-11/CPT molar proportion no higher than 5. Parameters of merit have been obtained for both methods. Analytical responses presented linear behavior in the in working range from the limit of quantification up to at least 348.0 ng of CPT or 440.2 ng of CPT-11 (deposited in the center of the substrate). Absolute limits of detection and quantification were 26.8 and 42.3 ng for CPT and 79.6 and 99.9 ng for CPT-11. A detailed metrological study was performed for the measurement of CPT and the combined uncertainty associated to the phosphorescence measurement was 16 percent. The method was applied for the quantification of CPT-11 in injectable solutions with recovery of 97.5 more or less 5.5 percent. For CPT, recovery in TPT based pharmaceutical formulation, previously fortified with the analyte, was 101.5 more or less 3.5 percent (measurement made at 367 nm of the second derivative excitation spectra). In analyte fortified urine and saliva, recoveries were respectively 102.5 more or less 3.5 percent and 102.5 more or less 4.5 percent (using non-derived spectra and detention at 570 nm of the emission band). Comparative tests between the SSRTP and HPLC-DF have been made and the results agreed (at a 95 percent confidence level). A comparison using different substrates (nylon and cellulose) was also performed in order to evaluate practical aspects, analyte signal intensity and the variability of the analyte and blank signals. The result indicated advantages in using nylon substrates for the phosphorimetric determination of CPT.